How to count sand? Very easy: the spoon after spoon, just as Ann has done it. It is still doable. A toy spoon is not so big. But is all sand the same? No What about the fact that, while we count the grains of sand, we can lose no grain. Then it must be feasible. In this manner, bit by bit, we come playfully to the symmetric difference of sets and to XOR gate, as well as to the distance of sets. Then we can also explain von Neumann numbers playfully. We demonstrate on examples: Logic Circuits as well as Finite State Machines. We look closer at the known codes: ISBN, IAN, bar code and QR. Besides, we put an accent on the essential questions of the synchronization in communication networks.