donut
youtube: https://www.youtube.com/watch?v=DEqXNfs_HhY&t=65s&ab_channel=LexFridman
"Donut math: how donut.c works" blog post by Andy Sloane: https://www.a1k0n.net/2011/07/20/donut-math.html
Deobfuscated code: https://www.dropbox.com/s/79ga2m7p2bnj1ga/donut_deobfuscated.c?dl=0