## How do I figure out tangrams?

Tangrams, which originated in ancient China, are great for practicing spatial skills — visualizing how parts can come together to make up a whole object. A tangram contains seven geometric shapes that fit exactly into a square. The classic rules call for assembling all seven polygons into a predetermined design, like an animal shape or a symbol.

Tans give you two large and two small right triangles, a small square, a medium-size triangle, and a parallelogram to work with, forms that you arrange to reproduce the outline of an image without any overlap in its individual pieces.

Getting the hang of geometry is a whole lot more fun with tangrams — and, what better way to exercise the 90% of our brains that experts say is waiting around to find work. The Internet provides lots of interactive examples for anyone who wants to practice their skills.

If you're looking for a secret to tangram success, you'll probably find it after you've completed a few (dozen or hundred) puzzles. In the language of geometry, here's a little insight into what happens when you start sliding pieces around to change, oh, say, a triangle into a square:

• Translate two triangles into a square by dividing a parallelogram right down the middle and scooting the shape on the right . . . right over to the left.
• Flip over the right half of a parallelogram at its horizontal mid-point. Now you have a triangle.
• Imagine a square; cut it in half diagonally from top right to bottom left. Rotate the left half all the way to the right. Looks like you have a triangle again!