In Beijing, a neurosurgeon named Jin Shanmu set out to understand brain ultrasounds and arrived, unexpectedly, at the edge of mathematical history. By running an AI system autonomously for sixteen hours, he produced a proof of Crouzeix's conjecture — a problem in numerical linear algebra that had resisted resolution for decades. The achievement is less a story about one man's triumph than a quiet signal that the boundary between human curiosity and machine reasoning is shifting in ways we are only beginning to measure.