Most tools for building a desktop app ask you to make a lot of decisions before you've written a single line that does anything: pick a framework, wire up a build system, set up a project structure, manage dependencies, configure a packager. Tessel throws all of that out. It's a small declarative programming language where a folder of .tsl files is the program — and the whole thing compiles down to a tiny native app for macOS and Windows. Here's a tour of what makes it interesting. A whole app in one block The clearest way to understand Tessel is to look at a complete program. This is a working counter app — not a snippet, the entire thing: You declare an app with a window size, a piece of state , and a tree of views — VStack , HStack , Text , Button — described the way they should look. Run it with tessel run counter.tsl and a real window opens. There are no project files, no imports, and no build configuration to write. If you've ever bounced off deskt...