Years ago, when I first learned of the Temporal Logic system called D, I made a puzzle postcard using the system and mailed copies to a few friends. They seemed to enjoy it, so I'm doing it again, for the Gift Exchange.

A lighting fast calculation trick- good for the not brilliant to seem brilliant and the youngster to be motivated to mentally calculate. It will be printed on paper and I will bring it with me.

In 1962 Martin Gardner published an article about a remarkable poem. As far as I know, his is the only scholarly article that has ever been published pertaining to this poem. There is a rich and particular connection between poetry and the more…

The included piece will be a decorated deltoidal icositetrahedron net, which can be colored and subsequently cut and assembled. Alternatively, those with a cutting machine can cut the closed regions on each face of the polyhedron to obtain an…

No-one really knows what quasicrystals look like. But we do know, from the diffraction patterns of X-ray crystallography, that they bear a resemblance to Penrose tiling. By combining artistic exploration with mathematical insight into the…

I have gifted an assortment of laser cut acrylic kits of simple mechanisms, including locks, engines, and other such mechanical devices. These were originally designed as physical diagrams for a book project, but are now being produced for sale.…

This is a standard trihexaflexagon with some extra crease lines. Cut it out and fold it up in the usual way, using tape or glue, adding the extra creases. The new degrees of freedom allow the hexaflexagon to swim along itself like Escher's fish, as…

A cube is used as a fair die of 6 faces. However, there are many dice of different shapes on the market. To make them fair, most of them usually have some symmetric shapes. I classify these variants of dice on the market into two groups. First, let's…

This configuration of thirteen sets of concentric circles grows out of an ancient tradition of visual alchemy. The faculties of imagination and intuition are employed as guides in the discovery of new and meaningful relationships between geometric…

This net is similar to those in my 'Cubes and Things' 3D coloring books, where I use playful patterns to accent symmetries of polyhedra. By truncating one vertex of a dodecahedron, it becomes a tridecahedron. (Do you think truncating all the corners…

(1) a description of how to construct Marjorie Rice's "versatile" together with six patches of copies of the tile that will fill the plane by translations.

(2) a sheet with 20 copies of the versatile to copy and cut out in order to…

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…

A laser-cut puzzle that illustrates a proof of Pythagoras’ theorem. The puzzle pieces either fit in 2 squares aXa and bXb, or in a hypotenuse square cXc. The shapes in the puzzle are taken from a known proof of Pythagoras’ theorem. To my surprise the…

A small bag containing twelve square tiles, each with a different pentomino marked on it. Instructions for use in divination are included, along with a set of puzzles using the runes.

I made pentagons of edges whose lengths are 1,2,3,4 and 5 in order and can be tiled the flat infinitive plane. And also hexagons of 1,2,3,4,5,6 edge length. A set of a few of them is my exchange puzzle.