Another (src: facultystaff.richmond.edu/~wross/PDF/Jor… ->artists trying to make a case that the Jordan curve theorem is not trivial. Which is almost always what it appears to be when one first encounters it, replaced by admiration for Bolzano for recognizing that the statement needed proof). pic.twitter.com/GSJt4rKtxf

PS: Both of these drawings are made by a single non-self-intersecting continuous loop, thus defining a clear inside and outside.