How it works
Pia is a potter, and one day her hands will be tired and she will want to stop. Retirement means living on what you saved, after you stop working.
She keeps her coins in a locked jar for later. Five coins go in every year, and the lock stays shut until open day.
Opening the jar early costs a fee of one coin in every four. The lock helps people keep a promise to themselves.
In the story the jar adds nothing: only Pia puts coins in. Real jars can have helpers, like growth or a boss's top-up coins, and other episodes look at those.