Whilst I'm on the subject of arcade machines, here's another two that I remember from the 1950s/1960s arcades.
Conveyor had a ball bearing running down a ramp to the large wheels. The wheels had long rods making up a kind of cog and between them was either empty space, that would carry the ball up to the next level but allow it to drop into a lose hole ending the game, or a short rod that the ball would rest on, passing over the lose hole and onto a higher ramp leading to the next wheel. The game had a single knob that when turned lifted an obstruction on the ramp so that the player could time the release of the ball bearing to slip into a slot with a short rod. Not easy! Getting the ball bearing right to the top and into the win hole gave you your money back and a free go.
Bullion was a simple game of chance with five slots each corresponding to a different prize amount and a pointer that whizzed round, until it was stopped with a distinctive clunk. If the pointer was pointing to the same prize amount you had bet on you won that amount of coins. Obviously the lower amounts had better odds of winning!
