Spot the Odd One

Spot the Odd One is a clean attention game. The screen fills up with the same symbol and exactly one of them does not belong. All you have to do is find it and tap it. There are 150 levels in total. The first ones are obvious, but as the grid grows from 3x3 to 7x7 and the difference is squeezed down to a couple of percent, you really have to look. The difference does not always come from the same place: sometimes the symbol itself changes (a dog among the cats, one squinting face among the smiling ones), sometimes one is a slightly different size, sometimes it is tilted a little, and sometimes it is just a touch more faded than the rest. After level 100 three new kinds open up: one sits off-centre in its square, one is slightly slanted, and one faces the other way. The first time a new kind of difference shows up, the game tells you once what to look for; after that you are on your own. You have three lives and every wrong tile costs one; from level 6 a timer joins in, and when the bar at the top runs out the level is gone. Finding it fast and clean builds a streak multiplier that scales your score. Every ten levels you get one of your lost lives back. Clear level 150 and the game ends for real: every life you have left turns into points and you get a gold-edged finishing card. A saved best score, a local top-10 leaderboard and a gold banner for every new record keep pulling you into one more run. No ads, no download, no connection needed; one finger on a phone, arrow keys on a computer. Fully readable in both dark and light themes.