This paper by Prof. Kevin A. Harrigan at the University of Waterloo presents a sample three-reel three-coin slot machine game with a bonus for three coins, and a true payback percentage of 85.6% when one or two coins are wagered and 92.5% when three coins are wagered. The player sees the winning or losing combination of three symbols on the payline as well as (a) the physical reels as they scroll by and (b) what is just above and just below the payline at the end of play.
“They Looked Like They Were Getting Rich on Polymarket— but None of It Was Real” | Wall Street Journal
June 22, 2026
By Katherine Long, Caitlin Ostroff, Neil Mehta and Brenna T. Smith “The prediction market has flooded social media with deceptive