Memorize the positions of numbers, then tap them in order.
Numbers 1 to N appear at random positions on a 5×5 grid.
Tap "1" first — the rest are then hidden. Tap them in order from memory.
You have 60 seconds, starting when you press Start. A wrong tap costs 2 seconds but does not end the round — keep looking for the same number. Clearing a round grows N by 1 (starting at 4).
Goal: when time runs out, your score is the highest N you cleared.
This game is famously based on a study where young chimpanzees outperformed humans at exactly this task, because they memorise spatial layout in a single glance instead of reading the numbers one by one. Copy that approach: do not recite "one, two, three", instead photograph the whole grid as a shape and remember where the cluster sits, not what the digits say.
The board hides after you tap 1, so spend your looking time on the positions of the higher numbers, which are the ones you are most likely to forget. Group them into a path your finger can trace — top-left, then dip to the middle, then the corner. Taps must go strictly in order, so you cannot skip a number you have forgotten. There is no mistake limit, but every wrong tap takes 2 seconds off the 60-second clock and you still have to find that same number afterwards — a moment of careful recall usually costs less than a string of guesses.