Sonic Pi allows you to compose music with code, and edit it on the fly.
I heard about it through Hacker News.
I installed it on Linux with:
sudo apt install sonic-pi
However, when I tried to launch it by running
sonic-pi I got the error:
jack server is not running or cannot be started
I found that others had the same issue, and the proposed solution was to run
qjackctl to start a jack server manually. However, I still got the same symptom.
After following those steps, I was able to get Sonic Pi to launch on Debian!