horch

float theta, var, th, sw, max, r;

void setup() {
  size(500, 300);
  strokeCap(SQUARE);
}

void draw() {
  background(#202020);

  max = 40;
  sw = map(sin(theta), -1, 1, 10, max);
  th = map(sin(theta), -1, 1, 0.8, 0.1);
  var = map(sin(theta), -1, 1, -0.1, 1.5);
  r = TAU/2;

  for (int i=1; i<5; i++) {
    noStroke();
    fill(#777777);
    float x = i*70+(i-1)*50;
    arc(x, height/2, 70+max, 70+max, 0, TAU);
    stroke(#FCD300);
    strokeWeight(sw);
    noFill();
    arc(x, height/2, 70+(max-sw), 70+(max-sw), i*r+PI*var, i*r+PI*(var+th));
  }
  theta += 0.0523;

  if (frameCount%2==0 && frameCount<121) saveFrame("image-###.gif");
}