How it works
A digital wallet is a note of who owns how many coins. At the Pebble Hill market, each person had a line on the Wallet Board with a name and a number.
The number is not coins to touch. When Maya sends Cy ten, no coin travels anywhere: the keeper just changes two notes.
The board will not let a send go past what the note shows, so a line never drops below zero.
A wallet has a lock-code, a secret for you and a grown-up in your family. It is not for friends, not for strangers online, and not for anybody who asks.