Mustache guard, dimple maker, automatic hat tipper, spaghetti fork, bird diaper, used gum receptacle. . . . All of these devices have been patented, but some look so peculiar that Murphy turns his offbeat catalog into a guessing game: first, he shows the patent diagram and offers one or more clues, with a choice of answers; then, overleaf, he identifies the gadget and tells a little more about it. Some items like the primitive washing machine were actually used at one time, and others never will be; let's hope the sunbather's toe rings patented in 1973 remain in the second category. As Murphy notes in explaining why such inventions are patented at all, ""You never can tell what might or might not intrigue people."" For a tinkerer's idle moments, this might do it.