For decades, the promise of quantum computing has hovered at the edge of the provable — a horizon that seemed to retreat as researchers approached it. Last week, that horizon was crossed: a quantum computer played a purpose-built game and won in a manner that mathematics itself forbids any classical machine from replicating. The demonstration, conducted by Quantinuum, does not merely suggest that quantum systems are faster or more efficient — it proves, with the finality of mathematical law, that a genuine and compounding gap exists between what quantum and classical computation can achieve.