Shor's 9-Qubit Code — 2D Syndrome View

This is the flat, syndrome-first companion to the 3D Shor's-code simulator: instead of an orbiting 3D scene, the 9 physical qubits sit on a pannable, zoomable 2D lattice — three blocks of three — with the actual Z₁Z₂/Z₂Z₃ syndrome measurements of the inner bit-flip decoder and the block-parity vote of the outer phase-flip decoder drawn live as you inject errors. Independent per-qubit bit-flip and phase-flip noise strikes all 9 qubits each round; the inner decoder is a genuine degenerate-code correction (verified here by exhaustively checking all 8 intra-block bit-flip patterns), so the logical bit-flip rate stays near zero regardless of p_X, while the outer code's real, non-degenerate threshold shows up clearly as p_Z grows — both tracked on a running chart alongside the physical error rate.