J. Quantum Circuit Notation

The drawing rules, one place (Ch. 15's reference card). Wires horizontal, one per qubit, time →. Gates: labeled boxes (1q), vertical-line-and-symbol (2q: ● = control, ⊕ = X-target, ●—● = CZ), boxed controls over multi-targets for fan-outs. Measurement: meter-gauge symbol → double classical line (or arc-arrow). Barrier: dashed vertical — "do not reorder." Classical control: box on the classical wire with an arrow to the conditioned gate. Special notations: SWAP as ×-crossing; virtual-Z as a tick; reset as a gate-boxed ↦0. Reading discipline (Ch. 15.1): paper diagrams are informal — always reconcile against the text's matrix or code. Text formats: this book's H 0 / CX 0 1 / M (Ch. 17.10); OpenQASM 2/3 (the interop standard — h q[0]; cx q[0], q[1]; measure q → c;). Qiskit drawing: qc.draw('text') terminal-safe, 'mpl' publication, timeline view for schedules (Ch. 44.7).