Cheap “organic” motion stacks a few mismatched sine waves on uv.x, uv.y, and sums like uv.x + uv.y. Normalize roughly to 0–1, then mix between palette stops. Not “real” noise — but close enough for wallpapers and loading shaders.
float m = 0.5 + 0.25*sin(uv.x*8.0 + t) + 0.25*sin(uv.y*10.0 - t*1.3);
vec3 col = mix(purple, cyan, smoothstep(0.2, 0.6, m));True procedural noise needs gradient-noise functions — try articles by Iñigo Quilez when you outgrow stacked sines.
Fold angle space for symmetry tricks.