These rooms have two downs. Things fall along −z, as anywhere, and also along −w, the fourth dimension: kata is down too, and ana is up. So you only stand where something holds you from below and from kata, tucked into a corner of the z–w plane. Step past the end of the wall kata of you and you slip down a slice.
You walk in x and y, and climb a step in z. But nothing lifts you ana except a ramp: walk off one where your slice ends, or into a wall, and it carries you a slice up in w, round whatever was in your way. A ramp holds you against w's gravity, too. The climb is finding the ramps; the fall is free.
Arrows walk · V or Space turns your sight: z up, then w up, then both downs side by side · Q E walk the camera round · Z undo · R restart · N a new room. The slices either side of yours show faintly.
Every room is built at random round a climb, and kept only if an exhaustive search finds a way up, finds none without its ramps, and (where it says so) none without its crates. Each one has a link of its own (⤴): the room is written into the link itself, so it opens the same room for anyone, for good.