The coin in motion: a token being added or spentThe stack: tokens on hand, eight at mostA token bucket rate limiter as a coin magazine. The hopper adds one token every 1.2 s until the stack holds eight, so bursts of up to eight pass at once; after that requests are allowed only as fast as tokens drip in. Each request pushes one coin onto the tray; with the stack empty the red lamp lights and the request is refused.