xkcd #3115: Unsolved Physics Problems
Title text:
'Tin pest' makes more sense to me. Tin just doesn't want to be locked down in a shape like that. I get it. But why would any metal want to grow hair??
Transcript:
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Source: https://xkcd.com/3115/
Bellman's lost in a forest problem: https://en.wikipedia.org/wiki/Bellman%27s_lost-in-a-forest_problem
Generalized moonshine: https://en.wikipedia.org/wiki/Monstrous_moonshine#Generalized_moonshine if the moonshine phenomena also exists outside the monster group
Snake in a box problem: https://en.wikipedia.org/wiki/Snake-in-the-box