01Five prompts a day. Everyone in the world gets the same five.
02Slide to your best guess, nudge single years with ←→, then lock it in.
03Dead on scores 100, and the score tails off smoothly from there — there's no cut-off, so even a wild guess earns something. Ancient prompts are marked more generously than recent ones.
04Post a score to claim your friend code, then swap codes to race each other.