Polar warp scrolling inward — an endless soft tunnel.

Screen coordinates are converted to polar form, with the angle driving one noise axis and the reciprocal of the radius driving the other. Because 1/r grows without bound toward the centre, the noise bands compress exactly as real perspective would, producing a convincing tunnel from a flat 2D lookup and no geometry whatsoever. Time is added to the depth axis so the walls scroll continuously inward, and a radial fade keeps the singularity at the centre from blowing out. Amber-to-blue walls with lime crests.