Earth, Moon and Sun Orrery
The Earth rotates 28 times while the Moon orbits the Earth once. The Earth rotates 360 times while the Earth orbits the Sun once. The Earth rotates 24 times for 1 rotation of the Sun. So the orrery is as accurate as it reasonably can be.
The Earth is a blue wheel flange, the Moon is a zinc chimney adapter, and the Sun is made from yellow semi circular plates. So the heavenly bodies are a suitable colour, size, and shape.