Halyard Multimedia Engine
Halyard is a hybrid 2D/3D multimedia engine that was used to build interactive training simulations. It started life as a 16-bit Windows application the late 1980s, and eventually wound up supporting rich scripting in Scheme, a custom IDE built around Scintilla, and a 3D engine based on Quake 2.
Unfortunately, we only have one small, low-framerate YouTube video of the 3D engine in action, though as of Spring 2014, we're looking to capture a much higher-quality video.
Some important directories include:
Common: backend code wx: wxWidgets-based UI runtime/collects/halyard: Scheme runtime