Pure data
Pure data is a graphical audio synthesis program. You can use it to code-golf.
Some reasons to want to golf in pd:
- While it is graphical the files are in readable ASCII which means you can easily tweak the source using an editor and changes to the program have predictable effects on the score.
- Golfing in pd has a lot of the weirdness of an esolang, but by learning it you actually learn a fun and useful programming language.
- You get to include cool pictures of your program in your explanation section.
I should also mention that if pure data were the LotM it would be an excellent opportunity to create some audio processing challenges. The normal wheelhouse of languages aren't natively well equipped for that sort of thing so these challenges seem to be pretty uncommon.
Since I would be remissed to nominate a graphical programming language with no pictures here's a picture of a pd program from this answer.
