tear

On the click, a jagged tear runs down the page from above where you clicked, leaving a white torn edge, and the page waits for the next one; if that takes a while, a loader shows at the cursor. Then the two halves pull apart and fly off either side, tilting as they go, each with a soft shadow. Going back, the tear runs up from the bottom.

The halves are two still copies of the page, cut along the same line with clip-path. The line is different each time: a few slow waves with a little roughness. The torn edges are thin paper-coloured strips along it.