p201_2

int circleResolution, s;
float radius, theta, angle;

void setup() {
  size(500, 500);
  background(20);
}

void draw() {

  strokeCap(SQUARE);

  background(20);
  translate(width/2, height/2);

  circleResolution = (int) map(sin(theta), -1, 1, 40, 70) ;
  radius = map(sin(theta), -1, 1, 100, 150) ;

  angle = TWO_PI/circleResolution;

  drawCircle(20, 240, 1.0);
  drawCircle(15, 20, .75);
  drawCircle(10, 240, .5);

  theta += 0.0523;

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

void drawCircle(int sw, int s, float scal) {
  strokeWeight(sw);
  stroke(s,200);

  for (int i=0; i<=circleResolution; i++) {
    float x = cos(HALF_PI+angle*i) * radius*scal*random(1, 1.5);
    float y = sin(HALF_PI+angle*i) * radius*scal*random(1, 1.5);
    line(0, 0, x, y);
  }
}