It takes about 10 seconds for Kevin Harrigan to lose three times on a Dynamite Diamonds machine, his 40-cent wager quickly disappearing each time as jangly electronic music plays on repeat and candy-coloured reels of kings, queens, wild cards and jewels flash by…

Harrigan, a slot machine expert and newly retired professor of computer game design at the University of Waterloo, is surprised you can bet up to $9 on every spin. At a nearby machine, Fortune Charm, you can wager up to $12 per play.

“I’m kind of stunned that they’re allowed to have that limit,” Harrigan said, pointing out that over time, players lose an average of about 10 per cent of the money they bet on such machines.