Same double-pendulum prompt, same host renderer, and two models picked opposite θ conventions. You can see it within seconds.
I ran the same double pendulum generation contract against Claude 3.5 Sonnet and DeepSeek V3 on OpenRouter, both under identical initial conditions (θ1 = π/2, θ2 = π/2, both angular velocities zero). The host renderer in public/workers/simulator-host.j…