mono

int circleResolution;
float radius, theta;

void setup() {
  size(400, 400);
  background(20);
  stroke(240);
}

void draw() {

  fill(20, 30);
  rect(0, 0, width, height);

  translate(width/2, height/2);

  circleResolution = (int) map(sin(theta), -1, 1, 3, 40) ;
  radius = map(sin(theta), -1, 1, 80, 160) ;

  float angle = TWO_PI/circleResolution;

  strokeWeight(1);

  for (int i=0; i<=circleResolution; i++) {
    float x = cos(HALF_PI+angle*i) * radius;
    float y = sin(HALF_PI+angle*i) * radius;
    line(0, 0, x, y);
  }

  theta += 0.0523;

  //if (frameCount % 4 == 0 && frameCount < 121) saveFrame("image-###.gif");
}