GOAL
A colour grid flashes on screen. Study it, then find the one cell that has changed colour. Tap it correctly to score and move to the next round.
RULES
- The grid is shown briefly — memorise the colours.
- The grid reappears with one cell changed. Tap it.
- Wrong taps flash red — keep trying, the clock is still running.
- The grid grows and the colour change gets subtler as you progress.
SCORING
Each correct find = round number × 100 pts. Later rounds are worth more.
Why this sharpens your mind
CHANGE DETECTION
Change blindness — the failure to notice visual changes — is one of the most studied limitations of human attention. Training change detection strengthens the focused attention circuits used in driving, reading, and spotting errors under pressure.