A blivet, also known as a poiuyt, devil's fork or widget, is an undecipherable figure, an optical illusion and an impossible object. It appears to have three cylindrical prongs at one end which then mysteriously transform into two rectangular prongs at the other end.
Paradoxical graphic figureEdit
In its most common usage, the word "blivet" refers to an indecipherable figure, illustrated above. It first appeared on the March 1965 cover of a Mad magazine bearing the caption "Introducing 'The Mad Poiuyt' ", and has appeared numerous times since then. An anonymously-contributed version described as a "hole location gauge" was printed in the June 1964 issue of Analog Science Fiction and Fact, with the comment that "this outrageous piece of draftsmanship evidently escaped from the Finagle & Diddle Engineering Works."
The graphic artist, M.C. Escher, used these types of figures as the basis for impossible three-dimensional compositions in many of his woodcut prints.
In December 1968 American optical designer and artist Roger Hayward wrote "Blivets: Research and Development" for "The Worm Runner's Digest" in which he presented interpretations of the blivet.