mexican_hat.pde

void setup() {
  size(640, 400);
  color[] c = {#000000,#0000FF,#FF0000,#FF00FF,#00FF00,#00FFFF,#FFFF00,#FFFFFF};

  background(c[0]);
  strokeWeight(2);

  int[] d = new int[160];
  for (int i = 1; i < 160; i++) {
    d[i] = 100;
  }
  float dr = 3.14/180;
  for (float y = -180; y <= 180; y += 6) {
    for (float x = -180; x <= 180; x += 4) {
      float r = dr*sqrt(x*x+y*y);
      float z = 100*cos(r)-30*cos(3*r);
      int sx = int(80+(x/3)-(y/6));
      int sy = int(40-(y/6)-(z/4));
      if ((sx < 0) || (sx >= 160)) continue;
      if (d[sx]<=sy) continue;
      int zz = int(((z+100)*0.035)+1);
      stroke(c[zz]);
      point(sx*2,sy*2);
      d[sx] = sy;
    }
  }
}

void draw() {
}