Mathematical analysis of wobbly tables.

Do you always get the wobbly table at restaurants and cafes? Don't despair. A physicist has proved that, within reasonable limits, it is always possible to rotate the table to a position where all four legs stand solidly on the ground.

Andre Martin was moved to study the problem because he was fed up with the wobbly tables at CERN, the European particle physics laboratory in Geneva, Switzerland, where he works on abstruse problems in high-energy physics.

Here's the full proof for the mathematically inclined (PDF format).