by Pater Tenebrarum
Imagine three men living on a small island. Toni is mining the local salt mine, and apart from him there are Pete the fisherman and Tom the apple grower and their families. They have a barter trading system set up: Toni exchanges his salt for Pete’s fishes and Tom’s apples, who in turn exchange fishes and apples between each other.
One day Pete says: “I have an idea. Instead of fish, I will from now on give you pieces of papyrus with numbers marked on them”. Papyrus grows in great quantities nearby, but has so far not been of practical use to any of the islanders. Pete continues: