I think feeding marbles to it repeatedly constitutes “looping”. Think of them as clock pulses going through a CPU. If you want to signal that the computation is

I think feeding marbles to it repeatedly constitutes “looping”. Think of them as clock pulses going through a CPU. If you want to signal that the computation is finished, you just direct the marble to a bucket (interceptor) instead of to the bottom. If you built a conveyor to automatically push marbles from the bottom back to the top, then you would have a slow but functional automatic computer.