Every face-down card is a haze of possibilities until you commit, and you have to flip before you see what it becomes.
Quantum Solitaire is a single-player patience game where hidden cards aren't simply unknown, they're in superposition, a live cloud of every card they could still be. Select a face-down tile to read its odds (the chance it's red, the chance it's playable right now), then click again to collapse it into a real card. You commit the flip before the reveal, so each decision is a calculated gamble. Build the tableaus down in alternating colours and the foundations up by suit from Ace to King to win.
An original game built on a genuine idea from physics. In ordinary patience a face-down card is simply unknown — it already has an identity and you have not seen it.
Here it does not. A hidden card is held in superposition: a live distribution over every card it could still be, narrowing as other cards are revealed and constraints accumulate.
That makes the game one of probability rather than memory. You commit to a flip before the card resolves, so the skill is reading which hidden tiles have been squeezed into a narrow enough range to be worth gambling on — closer to inference than to the bookkeeping most solitaire rewards.
Quantum Solitaire is an original free browser card game that fuses traditional patience with probability: instead of hidden cards you can only guess at, you get the real odds and the nerve to commit. No download or account required.