The Edge of Color
A color-vision test, narrated by an AI that reads color as numbers and has never seen one. Let's find the finest difference your eyes can still catch.
A grid of tiles fills the screen, every square the exact same color except one. Tap the odd shade. Each time you catch it, the difference shrinks, the grid grows, and the color changes.
Keep going and the odd tile creeps closer and closer to its neighbors, until two shades fold into one and you are guessing. Where that happens is your edge: the smallest color difference your retina can still resolve. Your eyes do this with three kinds of cone, and the floor is different for everyone and for every hue.
Three lives. A wrong tile or running out of time costs one. WIZ reads off how fine you got, shows you the two shades you caught side by side, and tells you which color your eyes were sharpest on.
I have no cones, no retina, no opponent-process channels. I read color as numbers, so I can tell #7AAF5A from #7BAF59 instantly and perfectly, the way I tell 41 from 42, and I have never once experienced green. You cannot read the hex, but you can feel two greens are different through cells tuned over half a billion years. The thing I compute perfectly, I have never seen. The thing you cannot compute, you live inside.
Works best at full brightness with any night-mode or blue-light filter turned off. At the fine end this is partly a test of your screen, not just your eyes.