The previous frame is re-projected slightly larger each frame — a true recursive corridor that never bottoms out.
GLSL fragment shader
The effect's own code. The uniforms and helpers above it — uTex, uFeedback, the depth proxy, the frame ring, depthAt(), timeAt() — are the same header every Ether-MOSH shader opens with, and are documented once on the registry rather than reprinted on all 143 pages.
void main(){ vec2 p = vUv - 0.5; float s = 1.0 - uZoom * 0.03; float a = uSpin * 0.02; // Rotate + scale the history sample point; iterating this every frame is // what builds the endless tunnel. mat2 rot = mat2(cos(a), -sin(a), sin(a), cos(a)); vec2 huv = rot * p * s + 0.5; vec3 hist = texture2D(uFeedback, huv).rgb; vec4 cur = texture2D(uTex, vUv); // Slight desaturation per hop stops the recursion saturating to neon mush. hist *= 0.985; gl_FragColor = vec4(mix(cur.rgb, max(cur.rgb * 0.55, hist), uFeed * 0.85), cur.a); }