Its a trivial app that demonstrates eye-focus tracking (just within the client, no data gets sent!) The wheel under your gaze will be stationery while the others rotate. If it detects you staring, all wheels will stop.
You may see some residual motion when you do stare, I’ve not fiddled with the settings to dampen out muscle impulses.
Spooky stuff, but you really have to see it for yourself.