Several years ago a colleague and I made paper copies of this famous old puzzle to distribute to prospective mathematics students. It is a fantastic puzzle, so I thought I’d post it here again.
From what I can tell, the puzzle was invented in 1871 by Sam Loyd (1842–1911), probably history’s most famous “puzzler.” It was printed on a card which was used by P.T. Barnum to promote his circus. The puzzle was called “P. T. Barnum’s trick mules” or “The famous trick donkeys.” Apparently Barnum distributed millions of them, and Loyd made thousands of dollars in just a few weeks from this single puzzle.
The goal of the puzzle is to arrange the three cards so that each rider is in his/her correct riding position on top of a donkey. (Here’s the original color version of the card complete with the solution written in reverse—to be viewed in a mirror.)
Print out the image below, cut out the cards, and see if you can put the riders on the donkeys.
Give up? Here the solution.
(Disclaimer: now that I look at these images again, I see that they aren’t Loyds’ original donkeys and riders. This may be a later version created by him, or a copy by someone else.)
If you like Sam Loyd puzzles, check out this fully digitized Sam Loyd’s Cyclopedia of 5000 Puzzles, Tricks, and Conundrums.