Someone stated in the early days of the war, a feeling that was reciprocated by the soldier in khaki and the sailor in blue, that a mechanical device would be the determining factor in ending the world conflict, favorably, of course, for the United States and her allies. 1 One of my common topics is the history of nuclear weapons. The "atom bomb" is a rich vein of history because its impact has been as much cultural as technical. Dramatic depictions like Christopher Nolan's Oppenheimer have recently enforced, perhaps even revived, the perception of nuclear weapons as an innovation that forever changed warfare. More quietly, historians and strategists tend to wonder if that is still true today, or if it was ever as true as was supposed—the conventional firebombing of Tokyo probably claimed as many victims as the nuclear attacks on Hiroshima and Nagasaki, for example. Besides, it's not unusual to hear people overstate the significance of nuclear weapons to WWII in a way that is obvious with a brief inspection of the timeline. The technology became available only very late in the war, and for that reason if no other, it must have had less of an impact on the outcome than other revolutionary wartime developments like radar. Why is it that radar, a complex technology that fundamentally changed the landscape of aerial combat, seems so pedestrian? Perhaps because the technology has far more non-military applications, and so is more familiar to our everyday lives. Perhaps because the development of radar was scattered between countries and institutions without the involvement of such intriguing figureheads as J. Robert Oppenheimer (although one wonders if this is because we have not looked as close; certainly radar figures like Henry Tizard had colorful lives as well). Perhaps because radar just isn't as exciting: it does not put on anything like the show of a nuclear detonation. Today, we consider another such step in military technology. This is an invention that forever changed the battlefield, and it's one that does put on a show. In fact, that has become the technology's main purpose. From the 1870 siege of Paris to the modern used car lot, searchlights have marked many of history's great conflicts—and great deals. The concept of electric light has been known since the very early 19th century. An electric arc lamp, or at least one of their ancestors, was demonstrated in 1806. Because of the widely known story of Thomas Edison's incandescent lamp, most people know that electric light had a very difficult journey from idea to practical device. That path was not as simple as what we are taught in schools: besides the several other inventors with a good claim to the lightbulb, incandescent lights were just one of a few technologies that developed in parallel. Before controlled incandescence, the principal form of electric light was still an arc. Arc lamps also did not fall to incandescent bulbs as quickly as you might think. Arc lamps remained the preferred choice for very bright, high-CRI lighting into the mid-20th century, and reached what will likely remain their ultimate form in the late 1960s, as the 15 kW Xenon arc lamps used by IMAX projectors. Along the way, arc lamps displaced many of the early forms of artificial lights: Oxy-hydrogen candles, known as "limelights," fell out of theatrical use. "Moonlight towers" began the displacement of gas lights for street lighting. And the military—the military readily adopted this new form of reliable, practical, powerful lighting. Calling In Light The effect of artificial lighting on military tactics could fill a book. I will focus on one narrow part of this story, but it will be helpful to set the stage with a few of the earlier developments. For much of the pre-electricity era of military history, artificial lighting was mostly a disadvantage. Fires, torches, and other practical sources of light were bright enough to reveal one's location but not bright enough to search anyone else out. Ironically, the main interest that military researchers had in light was often to suppress or conceal it. The chemical light technology developed for theaters and displays had promise, though. One of the first recorded uses of a powerful light for a military venture (and, as far as I can tell, the very first recorded use of a searchlight) came in the context of the American Civil War. The Union Navy sought to economically attack the Confederacy by maintaining a persistent blockade on southern ports; the Confederacy sought to maintain trade, often by sending out "blockade runners" under cover of night. A Union ship, perhaps frustrated by firing aimlessly into the dark, improvised: a theatrical light was mounted to a crude reflector, forming the first naval searchlight. It wasn't a very good one, it was dim and unfocused and the sailors struggled even to keep it lit under maritime conditions. It was good enough, though. By first following the sound, and then casting the light, the Union ship was able to engage the Confederate vessel even on a moonless night. Amusingly, while this incident is widely described in histories of military signals and lights, I have found none that state the outcome. Perhaps it was unfavorable to the victors. Electric arc lamps were far more suitable to military use: simpler to operate (although not as simple as we might today expect), more flexible in their placement, and by the end of the Civil War brighter. The 1870 Siege of Paris, part of the Franco-Prussian War, was a bellwether in the history of military aviation. Cut off on the ground, the French made extensive use of balloons (a technology they had pioneered in the 18th century) to move people and mail. In the process, several records for aerial travel were set. The French enjoyed air superiority and had little need for air defense, but the situation on the ground was much more troublesome. Prussian forces mounted lengthy artillery bombardments, causing devastation limited mostly by the range of their cannons. For the soldiers manning Paris's fortifications, it was important not only to keep attackers outside of the city, but to keep them as far away as possible. Paris, not for nothing known as the "City of Light," had seen demonstrations of arc lamps back to 1850. The invention of the arc regulator (which advanced the carbon rods to keep the arc intact) and improved batteries made the lights more practical by 1870, and during the early days of the siege "electricians" were hastily recruited to the city's defense. They manned a variety of arc lamps installed around the city, limiting the cover of darkness for nighttime assaults. At the summit of Montmartre hill, a position with a clear view over one of the most vulnerable parts of the city's defense, they installed one of the most impressive lights ever built. Not only was it larger than the others, it could operate for longer: the power supply was not a battery, but a dynamo powered by a steam engine. Besides that leap into modern design, the Montmartre light also presents an early example of "tipping and cueing" in intelligence gathering. French intelligence agents, having caught wind of a surprise attack, sent a message to Montmartre where the light's skilled operators aimed it by heading and elevation before applying power to catch the enemy in quite a compromising position. A decade later, the military searchlight had become a standard technology. The Royal Navy regularly equipped ships with dynamo-powered, carbon-arc searchlights starting around 1882. They found that, besides their role in aiming weapons, searchlights could be something of a weapon on their own. Aiming searchlights back at coast defense artillery positions not only exposed them to incoming fire, it also dazzled the gunners and frustrated their efforts to accurately aim at the ships. This principle was memorably demonstrated by a 1903 US joint maneuver exercise, in which the Navy's Atlantic Fleet mounted a simulated attack on Long Island Sound. All together, on cue, the ships trained their searchlights on the main defensive battery at Fort Michie. The soldiers at the fort didn't manage a single shot, they were so blinded by the lights—and limited in their ability to even move around the battlements, since they could so plainly be seen (and fired upon). As the military developed searchlights, they were quickly applied to civilian use. Limited availability of electricity, and limited need for such powerful lighting, meant that searchlights wouldn't yet become part of the urban landscape. They were reserved for special events, especially those with an emphasis on technical demonstrations. Of course, such events were bounteous around the turn of the century in the form of various world fairs and expositions. Perhaps the first use of searchlights as a device for entertainment came at the 1893 Chicago World's Fair, which was extensively lit by electricity. A total of 17,000 horsepower of steam engines (so, yes, presumably steam horsepower, a curiously different unit from the one we are familiar with today) powered thousands of arc lights. Most of these were for illuminating the fairgrounds and its many monuments, but some were installed for the sake of light itself. On the roof of the Liberal Arts Building, a searchlight claimed to be the most powerful yet made could light a newspaper well enough to comfortably read at a distance of eight miles. Of course, it was more than just a book light—it was a way to attract attention. Unlike the military context, civilian searchlights were deployed specifically to be seen. Rooftop searchlights became a common feature of large expositions, and by lazily searching the sky they established an atmosphere while guiding curious onlookers to the site of the event. Even this early, it was known that searchlights could be a powerful form of advertising. At the Chicago World's Fair, the upstart Cloud Projector Company demonstrated a searchlight with a lens system that could focus a slide onto the cloud layer. It was literally a cloud projector, in the modern sense, and giant words floating ethereally in the sky announced the fair's upcoming special events. In 1901, the Pan-American Exposition was underway at Niagara. Among the attractions was a demonstration of electrical arcs produced by a 40 kV transformer recently installed at the Niagara Falls power station. Alongside that light show, a second, more controlled form of arc was displayed: searchlights. These were described as an application of military technology, and specifically of military signaling technology. Searchlights were installed atop the "Electric Tower" at the exposition grounds, and at a viewing tower erected at Niagara Falls proper. At night, the two lights—22 miles apart—were each plainly visible from the other tower. The military was, of course, well aware of this potential use and as soon as searchlights had been installed on Navy ships they came into use as a means of communication. Extensive newspaper coverage of the Exposition means that we know more details of these machines. The searchlights used for the tower demonstrations had 30" reflectors, and consumed 80 amps at about 50 volts for 4 kW give or take. This was indeed a very bright light for the time, and at the Exposition, the searchlights were swung around among various targets. "As the beams of the projectors sweep across country," The Virginian-Pilot wrote, "the residents of the villages and country places will enjoy the illumination." Excitement for the lights was such that newspapers throughout the region published Morse code tables, in the hope that anyone in the region could decipher news bulletins that were sent from the signal lights. Watching the Skies Electric light is far from the only invention to make a dual appeal to spectacle and the military. From the Wrights' first controlled flight in 1903, it only took about seven years for the Navy to envision the aircraft carrier. The 1911 Italo-Turkish war featured armed biplanes, and as the hostilities of the First World War opened the US Army flew airplanes into Mexico, in pursuit of Pancho Villa. In 1915, the Austro-Hungarian Aviation Troops bombarded the Serbian city of Kragujevac from biplanes. Serbian soldiers fired on them with small arms, but had no success. A private, though, got a lucky shot with an artillery gun. This was the first instance of ground-air combat, and the first use of air defense. By the latter part of WWI, aircraft were in routine use as both bombers and fighters. One tended to lead to the other: our 1915 takedown notwithstanding, bombers and reconnaissance planes enjoyed almost complete freedom of the skies in the first few years of the war, until Germany's fighters presented meaningful resistance. Ground-based air defense lagged behind, but in an interesting turn of aviation history, the held-over use of tethered balloons as observation posts provided a key motivation for improved anti-air artillery. These balloons were conspicuous and almost defenseless, so ground-based escorts accompanied them. Balloons—and in the case of the Germans, Zeppelins—remained an important part of WWI air units. Besides their ability to hang around for an extended period of time, airships could carry much larger payloads than early bombers. Zeppelins occasionally loomed over London, raining down the era's most sophisticated destruction, from 1915 to 1917. These lumbering vessels had their vulnerabilities, though. Big, slow, and flammable, they were easy to take out with artillery fire if you could spot them. German air raids were conducted at night, and by the end of the war Zeppelins were being painted a non-reflective black. By 1916, a network of 258 searchlights across England hunted the skies for airships. There were as many anti-aircraft guns, using the pencil-beams of the searchlights as aiming guides. Air defense was so new at the time that little military doctrine had developed around it, and Britain's first searchlight units were found in the Royal Engineers. As in France, the searchlight operators were known as electricians, specifically the Electrical Engineers. These units had actually formed prior to the outbreak of WWI, for the purpose of coastal defense. None other than Chief Scout Lieutenant-General Robert Stephenson Smyth Baden-Powell (yes, the 1st Baron Baden-Powell) had improvised the use of a chemical searchlight to keep ships away from a besieged town during the Second Boer War; the Electrical Engineers had relieved the use of chemical lights in South Africa when they arrived with arc lights. By 1914, the Electrical Engineers had six companies in London as part of the Territorial Army. With the outbreak of the World War they were immediately put into service, as were other Anti-Aircraft Searchlight companies across Britain. Soon, other companies were deployed closer to the front in Europe. 1910s carbon arc search lamps were not always easy to operate. Most military searchlights by that time were built on the back of trucks, with combustion engine dynamos as a power supply. A typical WWI searchlight unit had three lights, five trucks, and 28 soldiers. Searchlight units became a natural home for other air defense technologies then under development, so that by the end of the war some units had acoustic reflectors (for detecting aircraft by sound) as well. One of the lessons learned during the First World War was that searchlights were quite flexible. Portable searchlights could be used for air-defense, or could be positioned on a hill to light the battlefield (and even dazzle attackers). A technique called "artificial moonlight" took advantage of the enormous output of carbon arc lamps by pointing a searchlight up at clouds and letting the clouds reflect the light back to earth. This dim illumination could help an infantry unit move at night; commanders had the moon on demand. On the other hand, searchlights were vulnerable. Experiments in mounting searchlights on airships to light the ground were of limited success, the lights made the position of the airship obvious and it would quickly be shot down. Similarly, as air-ground combat techniques evolved, searchlights became the first target for incoming enemy aircraft. Destroying the searchlights meant that anti-air guns were firing blind. Even after the First World War established searchlights as a defensive technology—their sweeping beams portending destruction—the public didn't lose its affection for a bright display. In an apparent homage to the use of arc lamps for both stage plays and film projectors, Hollywood's Egyptian Theater had searchlights atop its facade from its opening day. Perhaps inspired by the 1895 installation of an ex-Chicago World's Fair searchlight in Pasadena, the Egyptian Theater's lights announced premieres by sweeping the sky—promotional searchlights learned from air defense, and ironically, the post-WWI fashion for major events was to aim lights upwards, rather than downwards at terrain as had predominated before the war. Grauman extended the concept to his other theaters, with both permanent and portable lights often used at the Chinese Theater. In 1930, for the opening of Howard Hughes's "Hell's Angels," 200 searchlights lined Hollywood Boulevard. The scene could have easily been mistaken for a major air raid, but instead it became part of Hollywood culture. Three years later, 20th Century Pictures adopted its memorable emblem, surrounded by beams of light. Hollywood's searchlights spread beyond just theaters. In 1931, Fisher Motors De Soto-Plymouth on Hollywood Boulevard opened under sweeping lights. Auto dealerships always wanted attention, and searchlights were the perfect combination of electrical modernity, show business spectacle, and mystery. Synchro Searchlights Searchlight technology advanced incrementally between the First and Second World Wars. Carbon-arc lamps remained the underlying technology, but features like automatic carbon regulators (that "fed" the carbon rods towards the arc as they burned away) and foot switches for easy control became standard. A common searchlight at the beginning of WWII might range from 8 to 24 kW, and by the end of the war the largest units reached over 100 kW. The greater innovation of that war was the integration of searchlights into electromechanical fire control systems. New electrical technology, specifically a clever device called a "synchro" or "selsyn," revolutionized searchlight units. A synchro is a way of electrically transmitting a position. Two devices, similar to AC motors, are coupled by a three-phase circuit such that rotating one will rotate the other in proportion. The two "ends" of the synchro will always have the same relative position, so that by putting a synchro transmitter in one place and a synchro receiver in another, you can remote control the position of a device like a searchlight. Synchros were immediately applied to "distant electric control," still a common term in marine searchlights. One of the main problems with the searchlight has always been its tendency to attract enemy fire. Early searchlights often had two operators sitting on chairs to the back or side, cranking wheels for azimuth and elevation. These two operators were often killed early in the engagement. By the use of distant electric control, a searchlight's operators could hide some distance from the searchlight or even operate it from a fortified position like a bunker. This turned out to be a superior way of using a searchlight anyway: operators directly beside later searchlights were practically blinded by the light reflected back by dust and vapor in the air. An operator some distance to the side had a much easier time seeing what was at the end of the beam. Many US air defense searchlights offered a backup, as well: a control crank at the end of a metal arm, called an extended hand control. Were the electrical control system to fail, a searchlight operator could at least stand ten or so feet off to the side and be that much further from incoming fire. Practical use of searchlights for air defense by WWII required adaptation to the better ground-attack capability of aircraft. Searchlights might be stored in a concrete bunker and rolled out on tracks for use, by soldiers who would quickly retreat from the searchlight to a hidden control point. If the searchlight was struck, the operators at least survived, and a well-equipped unit would have a second light ready to go. The purpose of the concrete searchlight shelters was mostly to ensure that a "spare" searchlight would survive the shrapnel from an attack on the one in use. The synchro could also integrate searchlights with other air defense equipment. Early in WWII, radar had not yet been fielded, and acoustic locators remained the state of the art. But they were now part of a unified system: two operators on a set of acoustic listening horns would spin cranks to adjust horizontal and vertical position until the sound of an airplane's engines was loudest. By synchros, this position was transferred to a searchlight control station. These stations resembled a large pair of binoculars on a sort of articulated mount. The base of the control station had readouts for the azimuth and elevation from the acoustic locator, and the operator started by turning wheels to aim the remote searchlight where the locator indicated an aircraft should be present. Once the aircraft was caught in the beam, the searchlight operator threw a transfer switch that placed the searchlight under control of the synchros in the articulations of the binocular mount. From this point on, they tracked the aircraft through the binoculars, and the searchlight followed automatically. The azimuth and elevation from the binoculars could be sent by yet other synchros to readouts at an anti-air control station or even directly to a firing computer that aimed guns. All of this required adjusting for the different locations of each of these components. A combination of old fashioned fire control techniques (placing each station along a common base line) and analog computers did that trick, already well-established technologies since similar computations were needed to aim guns in consideration of gravity and wind. Speaking of a common baseline, it is also worthwhile to discuss the use of searchlights in coast defense during WWII. For a period of the war, the US feared a naval attack, particularly on the West Coast. Similar systems were widely deployed for firing artillery at attacking ships. A set of observation stations, placed along a common baseline, took azimuth readings to enemy ships. Those readings were reported by messenger, and later transmitted by synchros, to a plotting room where a mechanical and later analog computer determined the position of the ship. Yet other computers, at fire control points, determined how to aim the guns. Because this whole system relied on baseline stations visually spotting ships through theodolites, it was much less effective at night. Searchlights were added to many installations, remote controlled by synchros from the baseline stations. Like the azimuth-indicating spotting scopes, two searchlights trained on a ship from a well-surveyed baseline gave enough information to compute a firing solution. Advancing technology obsoleted the whimsical acoustic locating horns. Infrared heat detectors, looking much like searchlights but operating more or less in reverse, were the first electronic means of detecting aircraft in the night. They soon gave way to the first radar sets. The SCR-268, introduced in 1940, was the US Army's first fielded radar system. Its huge beam antenna had three operators on a bench hanging from the back, spinning cranks to adjust the antenna position until oscilloscopes showed the strongest possible return. The SCR-268 was a drop-in replacement for the acoustic locators in searchlight units, but it was far more effective. Skilled radar operators could place an aircraft accurately enough that it was centered in the searchlight beam before the light was turned on. Besides giving enemy pilots quite a surprise, this gave them little time to evade or return fire before anti-aircraft guns were zeroed in from the searchlight. The British developed a more refined version of the SCR-268 called the Searchlight Control Radar. It is notable for its far more compact design, small enough that its antennas were mounted directly to the searchlight under control. The result is almost cyberpunk, a 1.5 meter light bristling with antennas, operators hanging from the sides. The SLC is said to have raised the chances of spotting an inbound aircraft with the searchlight from 1% to 90%. I put a lot of time into writing this, and I hope that you enjoy reading it. If you can spare a few dollars, consider supporting me on ko-fi. You'll receive an occasional extra, subscribers-only post, and defray the costs of providing artisanal, hand-built world wide web directly from Albuquerque, New Mexico. Consider a typical World War II searchlight, the GE Model 1942, introduced the year that its model number suggests. This 60" searchlight came on a trailer, with a second trailer up to 600 feet away for the 12 kW diesel power plant and the control station up to 300 feet away. What we might now call accessory interfaces allowed the searchlight to receive synchro signals from a locator and send them to a firing computer. These searchlights still required quite a bit of maintenance, and they provided features to ease that work, like a work light inside the searchlight drum for replacing the carbon rods. The Second World War also brought about a renaissance in aerial searchlights. Mostly abandoned in the First World War because of their tendency to attract fire, searchlights returned to aircraft for a decidedly nautical use. Submarines, all diesel-electric during WWII, typically surfaced at night to run their engines and charge their batteries. The first submarine-hunting aircraft used compact carbon arc searchlights to pick submarines out of the dark. The system was remarkably effective, and prompted a change in strategy for diesel submarines, which had to rely on their own anti-aircraft weapons rather than mere stealth. Radar complemented the searchlight, but only for a short time. Radar locators for searchlights were basically an interim measure, making the best use of early radar sets that were sensitive enough to detect aircraft but lacked the spatial resolution to locate them precisely. Radar engineers, especially in Britain, made rapid improvements. For anti-submarine warfare, for example, shortwave radar systems were far more sensitive. It wasn't long before radar could directly guide anti-aircraft weapons, as well. Military searchlights had a role to play all the way through the Korean War, but a much reduced one. Anti-aircraft detection and firing is now firmly the domain of electronic warfare: radio waves, not light beams, search our skies. Surplus Light The declining relevance of searchlights to the military proved an enormous boon to their civilian use. Searchlights were tremendously expensive, so promotional use had been limited to major events like world's fairs. During the war, on the other hand, the Army had built thousands of them. Afterwards, through the War Surplus Administration, it parted with most of them at bargain rates. Entrepreneurial spirits, many of them veterans of the war, purchased secondhand air defense searchlights and offered them for advertising. Just about any auto dealership could afford to hire a searchlight for a sale, and many did. In California, it became traditional for dealerships to bring in searchlights to announce the new model year. There is a bit of moth in every human being, operators of giant searchlights have found. Whenever a searchlight is probing into the night sky, motorists are apt to go blocks, even miles out of their way to track down the source. [^2] Growing up in Portland, I remember seeing strange lights in the sky and searching for their origin. The searchlights utterly fascinated me, even if the source inevitably turned out to be another car lot. In New Mexico, promotional searchlights are rare, although not unheard of. The predominant weather may be a factor, since cloud cover makes searchlights more obvious. But it's mostly a matter of geography: the largest concentration of military searchlights was on the West Coast, and many overseas units were returned to West Coast ports. Los Angeles became the capital of the searchlight because they were cheapest there. There are still WWII military surplus searchlights in promotional use, but far fewer than there once were. Parts are hard to come by, and the operation of carbon arc lamps is a less familiar skill. Most of these searchlights are eighty years old, and built to designs that would have been familiar one hundred years ago. Because of radar's dominance, the military has little need for such powerful lights and no longer buys them in quantity. Promotional searchlights have once again detached themselves from air defense, developing as a separate industry. Modern searchlights use Xenon lamps, similar to carbon arcs in their use of an electrical arc as the light source, but far more refined. The arc is confined in an environment of Xenon gas, which practically eliminates electrode wear. Companies like Luminator make several-kW Xenon searchlights that can be mounted to aircraft, the main remaining use of searchlights for tactical purposes. Promotional systems have become much more specialized: Sky Tracker makes a popular system that mounts four 2 kW or 4 kW Xenon searchlights in the bed of a pickup truck. The four lights are attached to a common cam that rotates them in a "clover leaf" pattern, quite nonsensical for the historic application of air defense. Nonetheless, that clover leaf or vortex pattern is probably what most people now think of when searchlights are mentioned. Fixed searchlights, of the type that graced so many World's Fairs, are now rare. The most famous in the US, if not the world, is the Luxor Sky Beam in Las Vegas. Often said to be the brightest light in the world, the tip of the Luxor pyramid contains 39 7 kW Xenon searchlights for a total of over a quarter of a megawatt, all fixed straight upwards. Even that light may be in its twilight years: since 2008, it has operated at only half power. Today, concerns of light pollution, impact on aviation, and a general sense that auto dealerships should not lay claim to the sky have led to a decline in searchlight advertising. We are perhaps fortunate that the Cloud Projector Company's plans for on-cloud advertising didn't pan out; our present advertising industry is dystopian enough. Still, I am but a moth, or at least I have the impulses of one. There's nothing quite like a searchlight. "The Daily Item," Lynn, Massachusetts, May 7 1919 p. 9. [^2]: "The Plain Dealer," Cleveland, Ohio, July 11 1961 p. 46↩

[Misc] Tubular

Here are the Vim forks I know about: Neovim: “a Vim-based text editor engineered for extensibility and usability, to encourage new applications and contributions.” Vim Classic: “a stable, long-term support fork of the ubiquitous text editor, maintained without the assistance of generative AI tools.” EVi: “a hard-fork of Vim v9.1.0 (Jan 2024) before AI was used in the project.” MacVim: “a macOS version of the Vim text editor, providing a graphical user interface for Vim, while tightly integrating with macOS and providing features specific to the platform.” This list doesn’t include Vim-inspired editors like Kakoune, Vim-style plugins for other editors like IdeaVim, or Vim “distributions” like LazyVim. Contact me if you know of other forks!

Thought I’d make a quick blog post about some weird behavior I’m seeing on iOS 27 and Dynamic Island live activities, that I initially thought was restricted to the Duo, but turns out affects everything. Yay. Maybe this post can save some others some time, and hopefully Apple can fix it. Long story short, ever since iOS 16.1 introduced “Live Activities”, where we can display handy little widgets in the Dynamic Island, there’s been a bunch of different configurations for showing things up there: something on the left, the right, when expanded, when two apps are showing things and yours gets a bit smaller, and on the lock screen. One interesting one is if you only need to show a small indicator in the Dynamic Island (screen recording indicator, electric vehicle charging status, etc.) you can do so, which just shows on the left on older iPhones, and on the Duo a single one below the camera cutout. Apple describes how to do this in their developer documentation (emphasis added): If you can’t find a solution to display views for leading and trailing compact presentations with limited width, provide a compact leading presentation that best represents your Live Activity, such as the view you use for the minimal presentation, and an empty view for the trailing compact presentation. The system hides the empty trailing view automatically. Unfortunately, in iOS 27 (and 27.1, and 27.2), this only half works, due to a new addition in iOS 27: isDynamicIslandLimitedInWidth. It’s a variable that basically tells you if the Dynamic Island is even narrower than normal, presumably because they knew the Duo was coming with its vertical Dynamic Island, but also because as of iOS 27, Live Activities now show in the Dynamic Island when the device is in landscape too. So it’s handy to know if you have a bit less space than usual. In this new narrow view however, it seems like they didn’t test all the configurations thoroughly, as if you provide EmptyView for that trailing compact presentation, it’s not empty at all, and in fact enforces a quite large minimum size so the Dynamic Island looks hilariously tall. In other words: The system hides the empty trailing view automatically Left: what it should look like. Right: reality You can imagine this is especially rough on the Duo, where navigation buttons, toolbar buttons, tab bar buttons, etc. are all competing for precious space on the right. But that’s only half true. It displays perfectly fine (hiding it) when isDynamicIslandLimitedInWidth is false (AKA how it always used to be), but in the new cases where it can be true, like the Duo and iPhones in landscape, that’s when it breaks. So tl;dr: In iOS 27, Dynamic Island Live Activities are improperly sized if you use the listed EmptyView configuration and isDynamicIslandLimitedInWidth is true. This makes it especially bad on the Duo, womp womp. Complications Now, you might be saying “That’s weird, I haven’t seen that behavior! This is nothing but hogwash!”. But it is not hogwash, just a little complicated. There’s basically three categories of apps. Apple apps Maps, for instance, displays this single, small Dynamic Island live activity perfectly well and sized, and has been beautifully compiled with the iOS 27.2 SDK. By all accounts it should show this bug, too! Apple apps don’t have to use the same APIs as us normies, so funnily enough through really cool tools like REA we can disassemble the iOS Simulator and see that it’s in fact true, the Apple Maps live activity just completely bypasses WidgetKit and instead just renders plain UIKit through MapsBannerViewController which shows the cute little cyan widget through a ManeuverAccessoryView and then for the hidden trailing view simply returns a DistanceAccessoryView with CGSizeZero, which iOS actually respects, unlike our paltry SwiftUI EmptyView. Third-party apps NOT updated to iOS 27 If your app hasn’t been compiled with any of the iOS 27 SDKs, it only knows about iOS 26, and thus doesn’t know about (or have to worry about) the new, troublesome isDynamicIslandLimitedInWidth property, so it just… displays perfectly well. Here’s the Rivian app, which hasn’t been updated for iOS 27 yet, which shows the Live Activity displaying perfectly sized on the Duo (indicating vehicle charging): (Technical disassembly detail for the nerds: iOS shows the app’s minimal config, a smaller config normally used when multiple apps are in the Dynamic Island together, rather than the normal compact config, so it bypasses this issue entirely.) Developers who updated their apps for iOS 27 Surprise! That picture from before? On the left is just me compiling with the old 26 SDK that works! Unfortunately if you are a good developer who updated their app for iOS 27 and all the new features, you kind of get punished through this bug, because your live activity displays the improperly sized way described above, and you can’t just use raw UIKit like Apple. So you’re kinda stuck where I am: do I ship a weirdly sized Dynamic Island experience for everyone? Do I shove something extraneous in the compactTrailing spot just so it doesn’t look as empty? Do I not update the app at all until Apple fixes this bug? Widgets are techincally a separate extension from your main app, so you could compile them with a different SDK (26) than your main app (27) which fixes this bug, but I’m not sure Apple approves of that. Apple On the bright side hopefully it’s an easy enough fix, treating EmptyView like you used to on iOS 26 and per the documentation (the part that is weirdly right beside the mention of the new API that introduces this craziness in the first place). Radar/feedback assistant ID: FB25301955 Easy reproduction code if you’re curious: import ActivityKit import SwiftUI import WidgetKit struct CircleAttributes: ActivityAttributes { struct ContentState: Codable, Hashable {} } struct BlueCircle: View { var body: some View { Circle() .fill(.blue) .frame(width: 20, height: 20) } } @main struct CircleLiveActivity: Widget { var body: some WidgetConfiguration { ActivityConfiguration(for: CircleAttributes.self) { _ in BlueCircle() } dynamicIsland: { _ in DynamicIsland { DynamicIslandExpandedRegion(.center) { BlueCircle() } } compactLeading: { BlueCircle() } compactTrailing: { EmptyView() // pls respect me } minimal: { BlueCircle() } } } }

Vicky, driving me home from O'Hare, got sixteen dollars for the best conversation I had in months. The last line is hers.