Blockade is a randomized 2-color turmite screensaver for OS X (download or try it in your browser).
It's written in Elm with a small native screensaver wrapper that embeds the Elm app in a webview. The whole drawing is actually done via CSS.
You will need Elm 0.17 platform and Sass to build the web part. Once you have those
cd html && make
This will build you the new version in html/build. The three files from this directory get bundled in the screensaver.
To actually run the screensaver from Xcode, use the approach outlined here.
Copyright (c) 2016 Esad Hajdarevic, licensed under the MIT License.