Richard Lee's Answer

float t = 0, p = 370, q = 220;
void setup(){
size(800,500);
}
void draw() {
  background(0,0,120);
  t = t - 0.01;
  noStroke();
  //x = p(|cos t|cos t + |sin t|sin t), y = q(|cos t|cos t - |sin t|sin t)
  circle((400 + (p * ((abs(cos(t))*cos(t)) + (abs(sin(t))*sin(t))))),(250 +(q * ((abs(cos(t))*cos(t)) - (abs(sin(t))*sin(t))))),60);
  fill(220,0,0);
}