An ant wants to travel from one corner of the Sierpinski carpet to the opposite corner using the shortest possible route. And his friend, a termite, wants to do the same in the Menger sponge. Can you guide them well?

Two transparency sheets chosen at random from a larger selection. Combining any two different sheets reveals a different secret image. Exchange recipients are encouraged to find each other and combine sheets to reveal all of the images.

My gift exchange item is called an X-Y Chart. It is a very unique chart of multiplication facts for elementary school students. My friend, Joe Speier, who was concerned about children learning their multiplication facts designed the chart. During a…

Bill Gosper shared this problem with me. He calls it the Tax Man Problem. In the province of Peculia Pecunia, you are paid on an annular basis. That is, you get a (unit radius) gold disk from whose center is punched a smaller disk which you donate to…

My submission is an image featuring six cubes that all look like scrambled Rubik's cubes. But only one is. The other five all have some error impossible to find on a traditional cube. Can you suss out which it is and thereby find The Real Rubik's?

The Martian Mayor Problem looks at designing square modular networks which create Euclidean distances between modules. The catch is that there are a limited number of tunnels (connections) between modules. This is a mostly open problem as far as I…

Noted high energy particle psychic Fermi Geller is conducting a study of detox particles in his lab. He has successfully generated 13 new particles of Woo-ium in his reactor, but he needs to move the particles into the numerologically stable…

This is a rolling block puzzle. Roll the block from the start location to the end location. Avoid the obstacles in your path, and don't roll the block over its beveled edge. It will take some decaflops to get to the finish!

This item is a postcard announcing The Book of Why, by Judea Pearl and Dana Mackenzie, a book to be published in May 2018 by Basic Books. This book confronts the hoary old adage, "Correlation is not causation," which has been taught to generations of…