From the site:

Cagire is a step sequencer where each step contains a Forth script instead of typical note data. When the sequencer reaches a step, it runs the associated script. Scripts can produce sound, trigger samples, apply effects, or do nothing at all. You are free to define what your scripts will do. Cagire includes a built-in audio engine called Doux. No external software is needed to make sound. It comes with oscillators, sample players, filters, reverb, delay, distortion, and more.