Blivet

The blivet is an undecipherable figure and an impossible object, consisting of a fork with 3 cylindrical prongs at one and, and two rectangular prongs at the other end.

The origin of the name has military connotations, indicating an unmanageable and unpleasant situation, while in the Vietnam war it used to indicate a rubber bladder for transporting fuel and lubricants.

This object first appeared in the June 1964 issue of Analog Science Fiction and Fact, where it was called "hole location gauge" by the anonymous submitter, who also commented that "this outrageous piece of draftsmanship evidently escaped from the Finagle & Diddle Engineering Works". It subsequently appeared on the March 1965 cover of Mad magazine, under the name of poiuy (a fictional name created by reading the letters on the first row of a keyboard from right to left).

Since then, it appeared several times under different names, including: Ambiguous trident, Three pronged blivet, Devil's Fork, Devil's tuning fork etc.

The classic blivet or poiuy

Another version of a blivet