arena same task, several ai models, measured https://arena.chernyakov.ai/ 2026-09-02T00:00:00Z Ilya Chernyakov https://chernyakov.ai/ three runners, one prompt https://arena.chernyakov.ai/runners/ 2026-09-02T00:00:00Z 2026-09-02T00:00:00Z Claude Fable 5.1, Fable 5 and Opus 5 built the same Spanish-learning endless runner from one prompt. play all three and see time, turns and cost.