!!! READ THIS !!! You may have problems running this via Snapcraft (non functional UI, no sound, etc), if so please download the binary or compile from source at; https://github.com/mrbid/Borg-ER-0
This is a very simple tone generator that allows users to draw an oscillator wave-shape and envelope, the oscillator can then be tuned by frequency and amplitude.
It's a pretty interesting toy and it can generate some interesting tones. It has it's limitations, but I found it eye opening what the contrast of limitations was in comparison to a tone generator with frequency modulation and other forms of synthesis.