A tiny frequency domain synthesizer for linux.
Check out tinyspec-cling for a slightly more heavyweight version with livecoding support!
Try:
$ ./play hacks/brokenconvo.h
For full list of examples, see the hacks directory. example.h has been well commented as a starting point for further exploration.
If your aplay is not working, you might want edit the play script to send the output somewhere else instead. The samples are stereo 44100Hz 32-bit floats.