#include "rmannotes.sl"
displacement crud(float dots = 3,amount = 100, thickness = 6, Km = .05)
{
  float magnitude;
  float ss,tt;
  float d, fuzz =.5;
  float disk;
  float radius;
  point center;

  magnitude = 0; 
  rotate2d(s, t, radians(70), 0.5, 0.5, ss, tt);
  ss = repeat(ss,dots);
  tt = repeat(tt,dots);

  /* dots */
  center = (0.5, 0.5, 0);
  radius = 0.2;
  d = distance(center, (ss, tt, 0));
  disk = 1 - smoothstep(radius - fuzz, radius + fuzz, d);

  magnitude += noise(s * amount, t * amount) * thickness * disk;
  P += -Km * magnitude * normalize(N);
  N = calculatenormal(P);
}