Hah, yeah that still catches out o4-mini and o3 too. Amusingly, adding "It's not the riddle." to the end fixes that.

(o4-mini high thought for 52 seconds and even cheated and looked up the answer on Hacker News: https://chatgpt.com/share/68053c9a-51c0-8006-a7fc-75edb734c2...)