const c = circuit(2);
// Step 1: uniform superposition over all 4 nodes
c.h(0); c.h(1);
// Step 2: oracle — phase-flip the marked node |11⟩
c.cz(0, 1);
// Step 3: Grover coin (diffusion) = H X CZ X H on each qubit
c.h(0); c.h(1);
c.x(0); c.x(1);
c.cz(0, 1);
c.x(0); c.x(1);
c.h(0); c.h(1);
// Step 4: measure
c.measure();
return c;