Sometimes an idea grabs you and refuses to go away - I might write about the Hornicule some day.

Even now I don't know why I took a pile of Meccano, some brass off-cuts, and a discarded fruit box (hardwood!) and made an orrery.

It modelled (badly, about 2% off) Venus, Earth, and Mars. That is, if they had circular orbits.

Orrery