int i=100, p=0;
void setup() {
  size(500, 500);
  background(255);
}

void draw() {
  background(255);
  stroke(0);
  line(p, p, p+10, p-10);
  line(p, p, p-10, p-10);
  fill(255);
  stroke(0);
  strokeWeight(5);
  triangle(300, 350, 200, 350, 250, 150);

  fill(200, 10, 10, 150);
  stroke(255, 0, 0);
  strokeWeight(10);
  ellipse(250, 500, 600, 300);
  if(i>=0) { i--; } else { i=100; }
  ellipse(250, 150, i, i);
  p++;
}