In highschool a friend and I build a multiplication circuit based on an AMV serving as clock frequency driver, pushing binary numbers A and B through an addition circuit and a latch producing the result A*B.
We freaked out when we were able to increase the frequency from 1Hz where we visually could see the calculation proceed via LEDs, to thousands of Hz and "instant" calculation.
We had to physically hit the manual begin-switch with great force, in order to prevent the switch from not going cleanly from 0 to control voltage, when we operated in the KHz clock frequencies.