The pieces themselves are the shapes of four and five equilateral triangles joined, also known to mathematicians as tetriamonds and pentiamonds. ("Tetrapentos" means fours and fives.) See larger sets of polyiamonds in Kadon's Mini-Iamond Ring and Iamond Ring.

Jacques' neat design of the symmetrical hexagon pattern in the 4" round tray has 5 extra unit triangles (black acrylic) that allow tiling of the most interesting designs. Outside the tray you can form an even larger number of beautiful shapes. See a fantastic and ever-growing collection of silhouette figures starting here on Jacques' website, along with detailed descriptions and explanations in 3 languages. Play them online on Thérèse Eveilleau's wonderful website (in French). Just click the PLAY button above.

Great fun for ages 6 to adult. Our hands-on set,     $20     (We ship anywhere in the world; shipping cost extra.)

Now also available as pocket edition in pouch:

Pocket Tetrapentos^TM

The same 7 pieces — all the shapes of 4 and 5 equilateral triangles joined — in silhouette black, with a nice repertoire of Jacques' shapes to solve. Below are a few samples from the instruction leaflet. In drawstring pouch,     $10     (Shipping discount)

See also Jacques Ferroul's Poly-Spidrons^TM, Stelo^TM, and La Ora Stelo^TM

Visit Jacques' blog Kaprompiloj (in French and Esperanto)
for many other great polyform explorations