There is a much older Taco Bell grift: the charity coin drop game. Drop a coin onto the bottom step of an acrylic spiral staircase in a little water tank and you get a free menu item based on the denomination of the coin. It was designed so that if you landed on the last 2-3 steps you had a chance, but any higher and the centrifugal force of walking it down the steps would send the coin off the edge. It was very random with poor odds.
But eventually employees got sick of changing nasty change water and left it empty. The physics were a little different, but it seemed to be sufficiently difficult. Rather than wafting around, the further the coin dropped the more likely it was to bounce off a step. The much more deterministic coin movement enabled a new strategy: walk the coin backwards off of the first step and catch the coin directly on the final step. After ~$1 of practice, I had years of 5¢ tacos.
But eventually employees got sick of changing nasty change water and left it empty. The physics were a little different, but it seemed to be sufficiently difficult. Rather than wafting around, the further the coin dropped the more likely it was to bounce off a step. The much more deterministic coin movement enabled a new strategy: walk the coin backwards off of the first step and catch the coin directly on the final step. After ~$1 of practice, I had years of 5¢ tacos.