The Chicago widget set is a retro 32-bit desktop design language for Flutter. It was discussed in the Building a desktop design language with Flutter session in Google I/O 2021.
This library is still under very active development. It also relies on very new features of Flutter and is likely to only work against Flutter on the master channel.
Specifically, this library is known to NOT work against Flutter 2.2, as it relies on commits that have not yet made it to the stable channel.
The example directory contains a "kitchen sink" demo of the widgets contained in the package.
There's also an interactive demo built for the web available at tvolkert.github.io