The colorful Hoberman Mini Sphere comes out of the box looking like a futuristic Christmas-tree ornament. It's a cross between a ball and a star, and measures 5.5 inches across. But pick it up by any one of its dozens of plastic points and this amazing little feat of engineering, or imagineering, expands neatly into a lattice-like globe that's 12 inches in diameter. The inventor calls it a trapezoidal icosatetrahedron; you could also call it a Bucky Ball, but either way, it's a fascinating exercise in complex simplicity. The structure is rigid enough to roll and throw, yet if touched in the right way, it will suddenly collapse again, curling in on itself like a defensive hedgehog. An enclosed pamphlet describes various tricks you can do--if you're prepared to practice. And it's so aesthetically pleasing that Mom or Dad may swipe it for a desk ornament.