Simon Willison builds Chirp Pong, a two-phone game using audio chirps

Simon Willison says he built Chirp Pong, a two-player Pong-style game where phones in static HTML exchange game state through audio chirps picked up by the web microphone API. The game was built with Claude Opus 5.5 Extra in Claude Code, and Willison says the networking approach works. The post does not give details on latency, reliability, or gameplay beyond that.