We present a rigorous, self-contained construction and full mathematical analysis of a CSS surfacecode on a 64x16 qubit lattice, encoding k=16 logical qubits in n=1024 physical qubits at distanced=8. All claims are supported by explicit algebraic definitions, geometric proofs, GF(2) rankcalculations, and executable Python code.
Guillaume Besnard (Wed,) studied this question.