Imagine an uphill slope with its steepness related to a coin's bias. Winning means moving uphill. Going from one game to the other is like switching between smooth and sawtooth profiles. In effect, any winnings that happen to come along are trapped by the switch to the other game before subsequent repetitions of the original game can contribute to the otherwise inevitable decline. The same type of ratchet effect can occur in a bag or can of mixed nuts, Abbott says.
Brazil nuts tend to rise to the top because smaller nuts block downward movement of the larger nuts.
The researchers suggest that similar strategies may operate in the economic, social, or ecological realms to extract benefits from what look like detrimental situations. Unfortunately, Parrondo's paradox doesn't work for the types of games played in casinos. Ball, P. 1999. Good news for losers. Blakeslee, S. 2000.