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A light moves around the grid, one square at a time. Hit match whenever the current
square is the same one it was N steps back — you choose N, or let it adjust itself. That's the whole
game; it gets harder because remembering exactly how many steps back is the actual work.
This trains attention and short-term recall in the moment, not general intelligence. It's modelled on
the n-back task used in memory research since the 1950s — whether practising it makes you sharper at
anything else is genuinely contested among researchers, so treat this as a focus exercise, not a brain
upgrade.
Compare with someone
Type a handle to see their best score at your current difficulty, if they've saved one here. There's no
general leaderboard — only people you name.
Keep your scores
Your best on this device is already remembered. Sign in with Bluesky and finished runs can be saved to a
record in your own repository instead — nowhere else, and nothing is sent unless you choose to save.