Bought a darning mushroom. It is a wooden mushroom. You put it inside…

Bought a darning mushroom. It is a wooden mushroom. You put it inside the sock.

I resisted this for two years on the grounds that a tennis ball works and a lightbulb works and my own fist works, and all three of those are things I already own. Then I used a real one and it turns out the shape is the entire point: it holds the hole open at the tension the sock actually sits at, so you are mending the sock as it will be worn rather than as it is being stretched.

Every craft has about four of these. Objects that look like affectation until you use one, at which point you understand that somebody solved this in 1840 and the solution was a small wooden mushroom.