Just an interesting rule config for VisualPhaser

ruleconfig.pde

  sim = builder(15, 3.3, 1)
    .rule(new RuleStep() {
      public float f(float x, float y, PhaseField field) {
        return (x * 1.6 - y * 0.9) * sin(field.dc(x, y)/(width+height)*8*PI) * 0.01 + PI;
      }
    }, 1)
    .rule(new RuleStep() {
      public float f(float x, float y, PhaseField field) {
        return pow(x*x+y*y, 0.5);
      }
    }, 0.05)
    .useColor(#FFFFFF, #E0E0E0)
    //.sinWeight(0.25)
    .build();