Mark the state
Build a Grover oracle for |11⟩. Put both qubits into an equal superposition, then flip the SIGN of the |11⟩ amplitude and only that one. The histogram will not move at all — every outcome stays at 25% — and that is the entire point. The grader checks amplitudes.
Stuck on the concept? Read Grover's Search.
Heads up: this one is graded on amplitudes, not the histogram. A correct oracle leaves every bar exactly where it is — the two charts above will match long before you are done.
Select a gate to see what it does, then tap a wire — or Tab to a wire and press Enter — to place it.
Pick a gate, then tap a cell — or Tab into the grid and use the arrow keys and Enter — to place it.
Generate a fresh target state drill at this difficulty. Every generated puzzle is verified solvable by execution before you see it — the generator runs its own solution through the same simulator and grader that will judge yours.