A landscape in four dimensions, just after rain, and the sun low behind you. You see the 3D slice of it you're standing in. The rainbow is every direction 42° from the point opposite the sun, a cone in 4D, and what you see of it depends only on where that point sits in your own frame.
Turn, twist and look into w, or move the sun, and the bow on your screen becomes an ellipse, a parabola or a hyperbola (the dashed gold line is the formula's). Look far enough into w and it's gone. Lean into w and the land itself turns fae. And pick its grain: tesseracts, or PLATEAU's other two seed crystals, Kelvin's foam and the 24-cell foam.
WASD walk · mouse turns and looks (click to grab it) · Z/C or the wheel twist · Q/E look into w · X square up. Phone: the stick walks, drag to turn and look. how it works · the physics · Four · the arcade