An interior designer has a dilemma. She has to move an amazingly heavy armchair which is up against a wall. The chair needs to be sitting so it is exactly beside its starting position and facing the same way.

If the only possible movement is to rotate the chair on any of its corners, how can the chair be moved to its new position?

This will take only three rotations:

1. Take an imaginary line perpendicular to the wall that goes through the center of where the chair will be.

2. Rotate upon the leg (A) that's away from the wall and nearest this imaginary line until the other leg (B) that's away from the wall is on the imaginary line (120-degree rotation).

3. Rotate A about B until it's the same distance from the wall as it was before (60-degree rotation).

4. Rotate B about A until the back of the chair is against the wall (60-degree rotation).

Posted by Charlie on 2004-08-30 14:06:16