Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic riffs on famous stories of scientific insight being sparked by vivid mental imagery. It starts with two well-known examples: Kekule reportedly envisioned a snake eating its own tail, which led him to realize that benzene has a ring structure, and Einstein imagined a man in an accelerating elevator to develop his equivalence principle (that acceleration and gravity are indistinguishable).

The punchline comes in the third panel, where the comic wonders what mental image inspired the scientists who discovered particle self-interaction. A physicist is shown thinking: "When nobody's observing, the particle likes to interfere with itself." The humor lies in the double entendre -- "interfere with itself" sounds like a euphemism for masturbation, while it actually describes the quantum mechanical phenomenon where a single particle can interfere with its own wave function (as in the double-slit experiment). The comic suggests that some physics concepts are inherently difficult to visualize without the mental picture sounding inappropriate.