Tangram is an ancient Chinese puzzle--a.k.a. the Seven Tricky Pieces--a small square, a rhomboid, and five triangles of three sizes that are all cut from the same larger square. These pieces can be arranged to form a wide variety of shapes. Most modern tangram puzzles are small, plastic, and not necessarily great fun to touch or see. But this handsome Square Root version stands out because it's big (7.5 inches on each side) and made of smooth, unpainted wood, backed with red felt. An accompanying 16-page booklet encourages kids and adults to experiment with the shapes by showing arrangements that form letters of the alphabet (Roman, not Chinese), numerals, geometric shapes, animals, and people. --Rebecca Hughes