If you are interested in something really simplistic to get into and slightly related, check out SUBLEQ and High Level Subleq. The C code can be like a one-liner if you want. (Although if you handle a few basic things with output buffering and spread it out a little its more like 13 lines https://github.com/runvnc/sq/blob/master/sq.c). This one might work better, don't remember https://github.com/runvnc/sq/blob/master/sq2.c

https://portal.mozz.us/gemini/biomimetic.me/subleq.gmi

All it does is output characters to STDOUT, but you can do really interesting things with that micro VM and and an ANSI graphics terminal. Also started messing with Tektronix vector graphics which xterm supports.