Any object with a simply connected surface can be smoothed out to look like a sphere.

ECONOMIST: Proof of the truth of the Poincar�� conjecture

In this example, the surface is not simply connected and any smoothed-out object looks like a torus with at least one hole.

ECONOMIST: Proof of the truth of the Poincar�� conjecture

Perched atop a pair of active shutter glasses are a couple of miniature LCD projectors, which bounce images from a connected computer onto a special reflective surface at a 120Hz refresh rate.

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