void setup() {
  size(700, 600);
  background (0,0,253);
  noStroke ();
  fill (253,0,0);
  arc (350,600, 700,700, radians (180), radians (360));
  fill (240, 150,0);
  arc (350,600,550,550, radians (180), radians (360));
  fill (250, 300, 0);
  arc (350, 600, 400,400, radians (180), radians (360));
  fill (0,0, 253);
  arc (350,600, 250, 250, radians (180), radians (360));
}