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Download and print today’s puzzle with the difficulty of your choice

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How to play

1. Triangles are grouped into the strips pointed to by the arrows

2. Two strips with the same letter make up a pair

3. Each pair must contain all the numbers from 1 to 12


The Monthai and the Thai pillows

The Monthai puzzle is inspired on the beautiful, traditional Thai triangular pillow (Mon Thai in Thai). The puzzle has an elder brother called Canario.

Thai pillow. Image courtesy of Thai Pillows

The Monthai and the tetrahedron

The Monthai puzzle actually lives in a a three dimensional object with four faces called tetrahedron. Strips of triangles appear split only when we unfold this object to represent it in two dimensions. To check this you can print and cut out the Monthai below. Fold it along the thick green lines, glue the flaps and you will get the tetrahedron. You will see that every triangle strip is now a single closed band that runs across each of the tetrahedron‘s four faces (use the dash patterns to guide yourself). Now, do you see how to obtain additional Monthais from this tetrahedron?

The Monthai and the Pyraminx

Uwe Mèffert’s Pyraminx is a tetrahedron with 3 slices per axis featuring independent rotation. If you have one you can also print the figure above on self-adhesive paper, cut out all the triangles and orderly stick them onto the Pyraminx’s triangular faces. Now, by rotating the slices, can you get additional Monthais besides the ones obtained from the previous tetrahedron? Hint: start by studying the rotations of the Pyraminx’s 4 vertices...

Pyraminx. Image courtesy of Speedsolving


© 2013 Miguel Palomo, all rights reserved

The Monthai puzzle is registered internationally at the Registro de la Propiedad Intelectual de Madrid (Spain)