You can't comb a tan egg flat without creating a cowlick
cross-posted from: https://lemmy.world/post/28431423
The theorem has been expressed colloquially as "you can't comb a hairy ball flat without creating a cowlick" or "you can't comb the hair on a coconut".
https://en.m.wikipedia.org/wiki/Hairy_ball_theoremOpen linkView original on lemm.ee
Good thing they're actually tori, topologically.