The gaming machines industry is big business. Today’s invention is a new variant.
A player causes coins to dropped somewhere onto a pile of similar ones resting on a flat plate. The plate has vertical edges on three sides. Eventually the pile becomes critical, so that adding a single coin will cause a ‘landslide.’
These events will vary in size each time a coin is dropped on the pile, so that a variable number of coins will fall off the open front edge of the plate into a prize tray accessible to the player.
Under these conditions (self-organised criticality) there will be a very small number of huge avalanches and a large number of very small avalanches (Frequently, the initial landslide will fail to trigger others and no coins will fall from the plate).
This combination would strongly encourage people to play, whilst actually paying out minimal amounts in winnings (statistically limited, over the long term, but occasionally giving the impression of uncontrollable ‘house’ losses).