One of the magazines--GENII, MAGIC Magazine or Linking Ring maybe--had an article about the trick where three pieces of cardboard are shown in two rows depicting, say, 15 leprechauns. By rearranging the three pieces of cardboard, one of the leprechauns vanishes. Does anyone know: 1) which magazine that article was in, 2) who originated the principle, and 3) what the name of the principle is--if it has a name.

Here's a link to a jpeg of the leprechaun trick:
https://i.guim.co.uk/img/static/sys-imag......a6bffcc4

Many thanks in advance!

----- Amado "Sonny" Narvaez

I do know it was made in two sizes. We still have the large one hidden away somewhere, but I'm not certain the smaller size is still around.

Martin Gardner called this the "Principle of Concealed Distribution". It exists in many forms, and is very old.

Perhaps its most famous incarnation was in Sam Loyd's "Get Off the Earth" puzzle, which was patented in 1896.

As far as I know, the first description of the principle can be found in "Rational Recreations" by William Hooper (1794) under the title "The Geometric Money".

"The Vanishing Leprechaun" was published by Pat Lyons and Bill Elliott in 1968.

A discussion of the principle can be found in Martin Gardner's "Mathematics Magic and Mystery" as well as in an article by David Singmaster which is available at: http://rmm.ludus-opuscula.org/PDF_Files/......_low.pdf

Greetings, Friends,

Well, leave it to my esteemed colleague Saxonia to dig up this early entry of an interesting principle. Following his lead, I hunted and found we can push the year back even a bit more to an earlier edition of the book he sites. Check this out:

https://ia802703.us.archive.org/18/items......goog.pdf

So, the full bibliographic data becomes:

W. Hooper, M.D., Rational Recreations, in which the principles of numbers and natural philosophy are clearly and copiously elucidated..., (London: Davis, Robson, Isaw, Robinson: 1782), pp. 286, 287.

Please note, the "Isaw" in the publisher's data may be misspelled; an ink blotch on the PDF scan makes it difficult to see clearly. Can someone clarify this bibliographic detail? Thanks

And thanks again to Saxonia for his eagle-eye pointing out this important contribution.

Thomas Henry