All constructions

Rotate by an angle on the board

Turns an object about a centre by an angle already on the board. Ruler and compass only.

All parts
Part 1 of 5: Rule OXStep 1 of 2Ruler

Turn X about O. Lay the ruler so its edge passes through O and X.

Keys: left and right arrows step, Space plays or pauses, Escape goes back to all constructions.