Tallow CoveIn the harbour town of Tallow Cove, neighbors traded without coins and kept score of who owned what instead. Bram kept one big book. When Ana paid Ben three coins, Bram changed two numbers in the book. But everyone had to trust one keeper, and one book could be smudged or lost. Then Dot had an idea: "What if everyone kept a copy of the book?" There would be five copies, all the same, and no single keeper at all. Each notebook listed every neighbor's coins: ten, eight, six, four and two. Then Ana stood up and said, "I send three coins to Ben." Everyone wrote it down, so Ana now had seven and Ben eleven. But Cy had a sneaky thought. He changed only his own notebook, so that beside his name it said sixty instead of six. Four notebooks said six and only one said sixty, so the many outvoted the one, and Cy's sixty was ignored. To send coins, you show a secret key that only you hold. Digital coins work the same way, as numbers kept in many shared copies, and they carry real risks.