Scroll down.
The light half of the page breaks into squares and the dark half comes through underneath. Two thirds order, one third noise: the bottom rows go first, with a little randomness so it reads like something coming apart, not a window blind.
And you're through.
The sweep is tied to this section arriving, not to the one you left, so it finishes while you can still see it. Scroll back up and it runs in reverse.
The end. Scroll back up to watch it again.