Quantum Lights Out

Nine qubits. Turn every light off.

Intermediate
About 6 min
No sign-in
One shot: nothing is saved

Moves: 0
Scrambled in: 4

Every light should end up definitely off.

Setting up the table…

Before you play

Each light is a qubit. It can be off (0), on (1), or glowing in a superposition. Two lights can even be linked so neither has a state of its own.

Your goal is the same as the classic puzzle: every light off. The twist is that not every light is simply on or off.

How to play

Pick a tool, then tap a light. Flip toggles a light and its neighbours. Hadamard turns it into or out of a glow. Link entangles two lights. Measure forces a light to choose.
Cyan and violet glows are superpositions that differ by phase.
Reach every light definitely off.

Your challenge

Switch every light off on Hard, using Link at least once.

Optional. Nothing is tracked, so the result screen is your scorecard.

Ideas in this game

Gates
Superposition
Entanglement
Measurement

Go deeper

Games are free play: no account, no score, no tracking. A free account adds the Academy, where lessons keep a streak and earn badges and certificates, and the Studio for circuits of your own.

Create a free account