First time I saw a running linux box in 1996 (or perhaps 1995), the guy said me. You see I can compile, do other stuffs, and look what happen when I move the windows. (Which sound pretty unfamiliar to me at this time). This was a classical application namely: xroach. Here is a "modern" equivalent to this killer app. Reproducible: Always Steps to Reproduce:
Created attachment 257571 [details] xcockroach 0.5 ebuild
upstream is dead; time to move on I guess.
Still compiles and runs fine though. But this is clearly no way for integration as it'll fail to display anything for almost all user (even 6 years before).