See also the 25-Holes Challenge.
You may win a silver dollar!

This sweet and innocent-looking set of 21 V-shaped trominoes (3 squares each) can entertain a four-year-old with simple patterns, yet infuriate a grown-up expert with tough challenges. Math professor Norton Starr originally commissioned this set to demonstrate proof of a theorem—that an 8x8 grid can be filled with V-trominoes no matter where you leave the empty space. We coupled this puzzle with a color-separation feature, then added an original concept by Oriel Maximé, of filling the Vs on grids around strategically placed barricades. The 28 "Bends" layouts cover four levels, from Easy to Expert. Other challenges and game rules are included. A special feature in the 44-page booklet is a pretty alphabet. All acrylic, 7 tiles each of 3 luminous transparent colors in 7" tray with engraved grid lines. You can choose from three color combinations. Ages 4 to Ph.D., 1 or 2 players. $42

This delightful rainbow set, all hand-inlaid acrylic, was an instant hit and never ceases to surprise us with its variations and versatility. The 21 double tiles ("dihexes") comprise all the ways 6 colors can be paired. Here's a sample tile. Add the 6 single hexes, one of each color, and a landscape of color matches, color patches, non-matches and non-duplications invites exploration. The hardest are solutions with no two of the same color in any row (the "Latin" arrays). Some things even 5-year-olds can handle, with relish. Build with 4, 5 and all 6 colors, and solve "Hexmate" patterns that challenge you to replicate them on the grids provided. Outside the 11" tray 89 other exquisite figures await, and you can create countless others. Includes three competitive games. For 1 to 5 players, ages 8 to adult.$95

In the beginning were Tangrams, a set of 7 tiles based on half-squares cut in half diagonally. Their basic shape was a square, and they date back to the 17th century. Here is their latest brilliant and colorful embodiment. True to their mathematical purity, the 20 tiles cover 16 squares and can form hundreds of figures. We start them as a "stretched hexagon" with color separation. Each color supplies 5 tiles, a "hand" that covers a 2x2 square and 63 other symmetrical shapes. And so can two hands, and all four hands, in ascending sizes. Explore figures with many edges and large enclosures, letters of the alphabet and picturesque designs provided in the booklet, and create your own. Play with color patterns as well. You'll never run out of challenges. For ages 6 to adult. $49

Nine easy pieces fill the encircled pattern in thousands of ways. You can have the "diamond" piece in any of 37 different positions, and form a large variety of shapes outside the ring, too. All acrylic, five-color mix in a 5˝" tray. For 1 or 2 players, ages 6 to adult. $29

This 15-piece two-color subset of Triangoes continues to delight us with its variety of shapes and color symmetries, even years after we originally explored it. Large tiles (one sample shown at right) are easy to handle, and progressively more sophisticated color themes can be explored. We offer Triangoes Jr. in 6 cheerful color mixes. For its 25th anniversary in 2012, we added a touch of silver. Suitable for 1 or 2 players (and several kibitzers), ages 8 to adult. $65

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