Here's a novel concept: 24 diamond-shaped tiles and 6 triangular tiles carry the 6 dominant rainbow colors in every combination (one sample shown at right). Join them so colors meet only their own shades or their neighbors in the spectrum. Patterns emerge as you rearrange the tiles. Illustrated booklet shows many interesting shapes to solve outside the 8½" tray, as well. It's proven to be one of our instant hits for all ages, 5 to adult. All acrylic, for 1 or 2 players. $55

7 finely crafted hardwood pieces (not tangrams) form 101 fine figures. This puzzle was first published by F.A. Richter in Germany in 1891. We have reconstructed all their original puzzle figures and added a few new ones. In drawstring pouch it's also a fine travel game, for ages 8 to adult. $39

How cool is this? This solution can easily transform into any tetromino (the 5 shapes made of four squares), also known as Tetris pieces. If old Archie only knew!

This 14-tile dissection is the oldest documented puzzle in the world, and the decipherment of Archimedes' rediscovered manuscript is a hot topic among historical scholars and mathematicians. Also known as the Stomachion, it even made the front page of the New York Times, December 14, 2003. Luminous transparent colors in a sculpted 7" acrylic tray. Long unanswered:  Just how many ways can this square be solved? On October 31, 2003, Bill Cutler's program found the full answer of 536 distinct solutions. (Read the full story.) How many other convex shapes can the 14 tiles make? Bernd Rennhak in Germany found all 637 solutions. He also found that the set can solve 13 of the 14 tetratan shapes. The permutations are staggering. An amazing fact is that each tile's area is a whole number, based on the square as a 12x12 matrix. That allows each color in our solution to have an equal share of the total area. Here truly is ancient genius made visible. Some of the tiles' angles have sharp points, so we recommend ages careful 10 to adult.$35

Challenge open to the world: Find a convex or symmetrical figure not yet discovered, and we'll send you a little prize.

This 7-tile square was inspired by the dissection patterns of Stomachion (see Archimedes' Square, above), the Diamond Puzzle of T. A. Snider, and the classical Tangrams. Tangramion has amazing properties of its own. One big surprise was that the square has only 10 solutions, compared to Stomachion's 536. To date, 93 convex shapes have been identified and solved. Only 33 mirror-symmetrical and 36 rotationally symmetrical shapes have turned up so far—partly due to the fact that none of the 7 tiles themselves is symmetrical. See these and many other clever and creative designs in the Tangramion booklet (.pdf file, 303KB). In warm Lucite colors of ruby, amber, topaz, in sculpted 7x7" tray. Color mix may vary. Endlessly entertaining and challenging for one player, ages 8 to adult.$35

Tangramion is a trademark of Serhiy Grabarchuk.

Nine geometric shapes form imaginative designs and can be used to test for and develop creativity. Black acrylic pieces in their little drawstring pouch are handy to take on trips. Because these are not a puzzle to solve but a tool for creating recognizable images, their use also encourages communication and provides artistic fun for ages 6 to adult. Can you guess? At left, boy with toy boat; at right, a fort. (Shipping discount) $12

Pentarose is one of our most gorgeous puzzles. Transformed pentagons and sections of stars are the very shapes that fit together without leaving holes. They are based on prototiles discovered by Sir Roger Penrose during research into non-periodic tilings. We've styled it in four luminous acrylic colors in an 11" circular tray, with a small easel included. Recommended for ages 12 to adult. $59

We've found some of the most marvelous books of geometric patterns, with polygons dancing in symmetrical formations that evoke the creative imagination. These four volumes of Images, geometric tilings by Roger Burrows, contain an infinity of hidden scenes, forms, patterns, potentialities. They stimulate visual creativity. Each book is 9"x9", with 48 sheets per book. Pages within a book repeat so you can experiment with variations. Each volume is a new and fresh collection. Each, $7