Eyeball.

Designers and front-end engineers spend all day judging things by eye: is that gap 24 or 28? Is this the same blue? Is it actually centred? Eyeball turns that into a two-minute daily game.

Five tiny tests, one score out of 500. Everyone gets the same puzzle each day, so you can compare with friends. Share your result as a row of squares, keep a streak going, and come back tomorrow.

The five tests

1. Gap. Drag the last box until both gaps are equal.
2. Hue. Match your colour to the target by eye.
3. Center. Put the dot at the exact centre of the frame.
4. Ratio. Resize the box to today’s ratio, like 16:9 or golden.
5. Timing. After the flash, tap when the target time has passed.

Each test scores 0 to 100 by how far off you were, so near-misses still count.

Small print

The puzzle is generated from the date (UTC), so there’s no server and nothing to sign up for. Your scores and streak stay in your browser. It works with touch, mouse or keyboard (arrows adjust, Enter locks), and the whole game is about 5KB of JavaScript.