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Jacques Ferroul's "TetrapentosTM"


These puzzles are laser-cut from transparent topaz and amethyst acrylic. The Lucite cut edges glow and make it easy to see the divisions between the individual pieces.

The colors differentiate the pieces by size. They are the shapes of four and five equilateral triangles joined, also known to mathematicians as tetriamonds and pentiamonds. ("Tetrapentos" means fours and fives in Esperanto.) 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. Start by placing the 5 triangles in a nice symmetrical array and then see if you can complete filling the circle with the rest of the pieces.

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,     $22     (We ship anywhere in the world; shipping cost extra.)

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Also available as pocket edition in pouch:

Pocket TetrapentosTM

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,     $12     (Shipping discount)

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See also Jacques Ferroul's Poly-SpidronsTM, SteloTM, and La Ora SteloTM

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

We regret that most of Jacques' web addresses are temporarily unavailable.
They will be restored soon. Please check back later.
His Kaprompiloj blog works fine.

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