Mohan Srivastava was given a scratch card as a gag gift. He is a geostatistician: his working life is spent estimating what is underground from the small amount of it that has been sampled, which is a discipline built entirely on the question of how much information a partial view contains.
He scratched the card, won three dollars, and then — waiting for a train, by his own account — looked at the design rather than the result.
The game was a tic-tac-toe variant. A row of numbers was printed openly on the card, and beneath the latex was a grid to be revealed. The open numbers were there to make the game feel interactive. What Srivastava noticed was that they were not merely decorative: the way they repeated across the card carried information about what was underneath.
Some numbers appeared once. Most appeared more than once. And a card whose singletons lined up was a winner.
Singleton School
A recreation of the flaw, not a live game. The rule: a ticket wins when three numbers that appear exactly once across the grid form a line. Read it before you scratch.
The Ontario game carrying this flaw was withdrawn in 2011. No claim is made about any game on sale today.
He tested it on a stack of cards and found he could pick winners without scratching them about ninety per cent of the time.
The next part is the reason this story is here rather than in the previous chapter. He worked out what the flaw was worth: sorting cards at a rate a person could actually sustain, buying only the winners, it came to roughly six hundred dollars a day. He was a consultant. He made more than that doing his job, and without the tedium of standing in shops buying scratch cards.
So he called the Ontario Lottery and Gaming Corporation to tell them.
They did not take him seriously — which is, to be fair, the correct default response to a phone call claiming the lottery is broken. So he demonstrated it instead: he bought a batch of tickets, sorted them into winners and losers without scratching any of them, sealed the two piles, and sent them by courier with a note saying which was which.
The game was pulled within days.
Nothing about the mathematics here is difficult. The whole insight is that a visible pattern printed on the outside of a card was correlated with a hidden result inside it — an information leak, of the kind that any statistician who works with partial data is trained to look for.
What is difficult is the part that came after the discovery. He is the only person in these six chapters who found a genuine, exploitable, repeatable crack in a lottery and chose to hand it back.