Last month, Google unveiled a significant interface update for Wear OS: Tiles. On updated watches, you can swipe from the main watch face to access new screens with quickly-accessible information, like fitness goals and the current weather forecast. The company hasn't provided developers with a way to create their own Tiles, but legendary Wear OS developer Sterling Udell has now fixed that problem.
Udell, maker of applications like TerraTime and Wearable Widgets, developed an unofficial app library and published it to Bitbucket for others to use. "Although the API detailed below is undeniably unofficial, it does use the official Wear system-level hooks to create and update tiles on the watch," he wrote in the project's readme file. "They're real tiles in the end."
You can try out a demonstration by signing up for the TerraTime beta program, and then installing the app to your watch. Once that's done, TerraTime appears as a Tile option, and it works just like the Google-made Tiles.
Udell notes that the unofficial library only allows apps to create a single Tile, but he did find evidence in the Wear OS app source code that Google may change that limitation — perhaps when the official API makes an appearance.