Glassby

"FreeCell hides nothing," Glassby says, bouncing a little. "Nothing! Every single card is face up from the very start. You can see all of them."

This matters more than it sounds, and one day Glassby got to show why.

A group of young squirrels came to the lab confused about the word lost. They had been playing the other kind of solitaire, the kind with a face-down pile and buried cards you can't see. Sometimes the solver said lost. And the squirrels wondered: did lost mean the deal was impossible, or just that the solver was unlucky with the hidden cards?

Glassby swept his magnifying glass across the table with a flourish. "Great question! Let me show you the difference."

First he laid out a deal of the hidden-card kind. "Here, lots of cards are face down. You can't see them. So you make choices without knowing what's underneath. When a deal like this is lost, you have to be careful. Knowing only what you could see, there was no way through. But you were playing partly in the dark."

Then he laid out a FreeCell deal. Every card face up, spread across the table, the whole thing plain to see. He held his magnifying glass over it and grinned so wide his cheeks nearly popped.

"Now look. Nothing is hidden. The solver can see every card, every move, the whole map. If the solver searches through every possible path and finds no way to win, that isn't bad luck. There's no hidden card that might have saved it. There's nothing left to discover."

A squirrel's eyes widened. "So if a FreeCell deal is lost..."

"...then it's a proof," said Glassby, practically vibrating. "It proves that this deal, exactly as it's laid out, can never be won by anyone, ever. It's not about the player. It's a fact about the deal itself."

The squirrels were quiet for a moment, taking this in. It was a strange and wonderful idea: that a game could be so open that a loss became a certainty, like a solved puzzle.

"Is that rare?" asked one.

"Very rare," said Glassby happily. "With four free cells, almost every FreeCell deal can be won. So when the solver really does prove one can't be, it's a little treasure. People who study FreeCell have found only a handful of them in huge piles of deals."