Sources page biographical material

6.AJ.1 TWO PRONGED TRIDENT
I have invented this name as it is more descriptive than any I have seen. The object or a version of it is variously called: Devil's Fork; Three Stick Clevis; Widgit; Blivit; Impossible Columnade; Trichometric Indicator Support; Triple Encabulator for Tuned Manifold; Hole Location Gage; Poiyut; Triple-Pronged Fork with only Two Branches; Old Roman Pitchfork.
Oscar Reutersvård. Letters quoted in Ernst, 1992, pp. 69-70, says he developed an equivalent type of object, which he calls impossible meanders, in the 1930s.

R. L. Gregory says this is due to a MIT draftsman (= draughtsman) about 1950??

California Technical Industries. Advertisement. Aviation Week and Space Technology 80:12 (23 Mar 1964) 5. Standard form. (I wrote them but my letter was returned 'insufficient address'.)

Hole location gage. Analog Science Fact • Science Fiction 73:4 (Jun 1964) 27. Classic Two pronged trident, with some measurements given. Editorial note says the item was 'sent anonymously for some reason' and offers the contributor $10 or a two year subscription if he identifies himself. (Thanks to Peter McMullen for the Analog items, but he doesn't recall the contributor ever being named.)

Edward G. Robles, Jr. Letter (Brass Tacks column). Analog Science Fact • Science Fiction 74:4 (Dec 1964) 4. Says the Jun 1964 object is a "three-hole two slot BLIVIT" and was developed at JPL (Jet Propulsion Laboratory, Pasadena) and published in their Goddard News. He provides a six-hole five-slot BLIVIT, but as the Editor comments, it 'lacks the classic simple elegance of the Original.' However, a letter of inquiry to JPL resulted in an email revealing that Goddard News is not their publication, but comes from the Goddard Space Flight Center. I have had a response from Goddard, ??NYR.

D. H. Schuster. A new ambiguous figure: a three stick clevis. Amer. J. Psychol. 77 (1964) 673. Cites Calif. Tech. Ind. ad. [Ernst, 1992, pp. 80-81 reproduces this article.]

Mad Magazine. No. 93 (Mar 1965). (I don't have a copy of this -- has anyone got one for sale?) Cover by Norman Poiyut (?) shows the figure and it is called a poiyut. Miniature reproduction in: Maria Reidelbach; Completely Mad -- A History of the Comic Book and Magazine; Little, Brown & Co., Boston, 1991, p. 82. Shows a standard version. Al Seckel says they thought it was an original idea and they apologised in the next issue -- to all of the following! I now have the relevant issue, No. 95 (Jun 1965) and p. 2 has 15 letters citing earlier appearances in Engineering Digest, The Airman (official journal of the U.S. Airforce), Analog, Astounding Science Fact -- Science Fiction (Jun 1964, see above), The Red Rag (engineering journal at the University of British Columbia), Society of Automotive Engineers Journal (designed by by Gregory Flynn Jr. of General Motors as Triple Encabulator Tuned Manifold), Popular Mechanics, Popular Science (Jul 1964), Road & Track (Jun 1964). Other letters say it was circulating at: the Engineering Graphics Lab of the University of Minnesota at Duluth; the Nevada Test Site; Eastman Kodak (used to check resolution); Industrial Camera Co. of Oakland California (on their letterhead). Two letters give an impossible crate and an impossible rectangular frame (sort of a Penrose rectangle).

Sergio Aragones. A Mad look at winter sports. Mad Magazine (?? 1965); reprinted in: Mad Power; Signet, NY, 1970, pp. 120 129. P. 124 shows a standard version.

Bob Clark, illustrator. A Mad look at signs of the times. Loc. cit. under Aragones, pp. 167 188. P. 186 shows standard version.

Reveille (a UK weekly magazine) (10 Jun 1965). ??NYS -- cited by Briggs, below -- standard version.

Don Mackey. Optical illusion. Skywriter (magazine of North American Aviation) (18 Feb 1966). ??NYS -- cited by Conrad G. Mueller et al.; Light and Vision; Time-Life Books Pocket Edition, Time-Life International, Netherlands, 1969, pp. 171 & 190. Standard version with nuts on the ends.

Heinz Von Foerster. From stimulus to symbol: The economy of biological computation. IN: Sign Image Symbol; ed. Gyorgy Kepes; Studio Vista, London, 1966, pp. 42-60. On p. 55, he shows the "Triple-pronged fork with only two branches" and on p. 54, he notes that although each portion is correct, it is impossible overall, but he gives no indication of its history or that it is at all new.

G. A. Briggs. Puzzle and Humour Book. Published by the author, Ilkley, 1966. Pp. 17-18 shows the unnamed trident in a version from Adcock & Shipley (Sales) Ltd., machine tool makers in Leicester. Cites Reveille, above. Standard versions.

Harold Baldwin. Building better blivets. The Worm Runner's Digest 9:2 (1967) 104 106. Discusses relation between numbers of slots and of prongs. Draws a three slot version and 2 and 4 way versions.

Charlie Rice. Challenge! Op. cit. in 5.C. 1968. P. 10 shows a six prong, four slot version, called the "Old Roman Pitchfork".

Roger Hayward. Blivets; research and development. The Worm Runner's Digest 10 (Dec 1968) 89 92. Several fine developments, including two interlaced frames and his monumental version. Cites Baldwin.

M. Gardner. SA (May 1970) = Circus, pp. 3 15. Says this became known in 1964 and cites Mad & Hayward, but not Schuster.

D. Uribe, op. cit. above, gives several variations.