Want to teach your child about simple mechanics and cause and effect, without a trip to the reference department at your local library? This toy is a future engineer's dream-- with dozens of gears, cranks, connectors, and interlocking plates, ripe for three-dimensional discovery. Because the toy is open ended, kids can build whatever they dream up, be it a monster engine for their imaginary solar car, or an intricate candy concoctor chock-full of moving parts. This 95-piece set is a good start, but if your kid likes it, you'll want to add more pieces to work with, as her creations grow in complexity. Underneath all that plastic is a simple but elegant design: kids will focus on the fun, but they'll be building on creativity, patterning, problem solving, and spatial reasoning, as their gears grow. (Learning Resources, $19.99)