Card 65 of 82
Piece of Paper on the Cactus
A man walks up to a cactus, looks at a piece of paper pinned there, and kills himself.
Solution: The man had been wandering lost in the desert and feared he was walking in circles. To test this, he pinned a blank piece of paper to a cactus and set off walking. When he came across the paper again, his fears were confirmed and he knew he would never find his way out.