What's stopping us from building useful quantum computers? And how long until we'll have them?

Some neat number tricks using numbers read backwards.

Eleven makes multiplication easy.

A quick look at an ancient problem.

The impossible becomes possible when you move into the third dimension.

A mathematical "paradox" explains why more roads don't necessarily mean fewer traffic jams.

Why there are only three regular polygons you can tile a wall with.

What does packing balls in higher dimensions have to do with getting your message across?