PhD student, Inria MOCQUA
Collect every path at the all-ones label: 1, 11, 111 or 1111. Choose a hole, then a gate. Leave holes empty to use identity when it is offered.
The white wires show the circuit. Below, each lane represents a bit string. Lit paths show amplitudes splitting, moving and interfering. Black dots mean + phase; white dots mean − phase. Larger dots mean a greater chance of that result.
Matching signs add; opposite signs cancel. Unlit lanes have zero amplitude. With just one surviving path, its overall sign does not change the result.
Yellow squares are H, red ⊕ gates are X, and green dots are Z. Linked dots are CZ. The two CNOT choices swap the control dot and ⊕.
Arrow keys move between holes. H, X, Z, I or 1–4 place gates. Right-click or Delete clears a hole; Ctrl/Cmd+Z undoes.
0 moves
Fill the holes to collect every path at the all-ones label. Matching signs add; opposite signs cancel. A single surviving path may have either sign.
PRO is the standard game. PROP adds wire crossings. Controlled PROP lets you use equations under shared controls.
Editor: place gates, then replace gates with holes. The goal stays all ones. Click neighbouring wires for a swap. Keep controls and targets on different wires.
Background: Delorme and Perdrix, control as a constructor; Blake, polycontrolled PROPs (MFCS 2026).