Odd One Out
Every round hides one different icon in a grid of identical ones. Click it before the timer hits zero. Each round the grid grows and the clock shrinks.
This game runs on visual search — the same skill used in proofreading a document or scanning an X-ray for something that doesn't belong. It's a real, trainable ability, and the two things that make it harder here (a bigger grid, less time) are exactly the two variables researchers use to measure it.
Symmetry helps: the grid is scanned faster in a sweeping pattern (left to right, row by row) than by jumping around randomly, since a consistent scan path means you only need to hold one row in memory at a time instead of the whole board.
Every round raises the stakes in the same two ways — a larger grid to search and less time to search it — so your best level is really a measure of how well those two pressures compound before your accuracy breaks down.
A grid fills with one icon, except for a single different one hidden among them. Click the odd one out before time runs out to advance.
Yes — each round the grid gets bigger and the timer gets shorter.
Don't hunt icon by icon — let your eyes relax and scan the whole grid at once. The odd one tends to catch peripheral vision as a break in the pattern before you'd spot it by checking each icon individually.