A circle is inscribed in a semicircle. The diameter of the circle and the radius of the semicircle are 12 units. Drawings can 'prove' mathematical statements.
Unit cubes form a larger cube.
Some faces of the larger cube are painted. Split a regular hexagon into three identical parts. Split a regular hexagon into six identical parts, at least two different ways. Split a regular hexagon into six identical kites. There are twelve different polyiamonds that contain six equilateral triangles each.