#include "rmannotes.sl"

surface demo()
{
  float fuz = 0.05;
  color surface_color = 1;

  /* tile coords */
  float freq = 4;
  float ss = repeat(s, freq);
  float tt = repeat(t, freq);

  color layer_color = 0;
  float d = distance(point(.5,.5,0), point(ss,tt,0));
  color layer_opac = 1 - smoothstep(0.3-fuz, 0.3, d);
  surface_color = blend(surface_color, layer_color, layer_opac);

  Ci = surface_color;
}