Minecraft 12-Tone random generator
The central element in the 12-tone generator is a module that has the function of playing a tone and then preventing that tone from being repeated. This is regulated by the position of the sand block. When it is at the top, it forwards the signal.
Simultaneously the mechanism checks whether all twelve tones have already been played. If this is the case, the entire generator is reset and the next series of twelve tones is used.
In Minecraft there is a building block that drops a random component into the game, the so-called dropper (on the right in the picture). This dropper ejects one of two items. Depending on which item it ejects, a different signal is passed on.