I tried to put up a link to the original "The Far Side" cartoon that depicts the above joke (which is not a "joke" at all but a cartoon) but the cartoonist, Gary Larson, has asked all persons to never post his cartoons, but to buy his books instead, so not only was the cartoon not available, but I couldn't have posted it anyway. Too bad, now anyone not acquainted with his demented humor will never know, and therefore will unlikely ever buy his books.