p112

float segmentCount, angleStep, radius, theta;

void setup() {
  size(500, 500);
  colorMode(HSB, 360, 100, 100);
  //noStroke();
  stroke(350);
  strokeWeight(8);
}

void draw() {
  background(350);
  segmentCount = map(sin(theta), -1, 1, 6, 12);
  angleStep=360/segmentCount;

  float div = map(sin(theta),-1,1,4.5,2.5);
  radius = width/div;

  beginShape(TRIANGLE_FAN);
  vertex(width/2, height/2);
  for (float angle=0;angle <=360; angle+=angleStep) {
    float vx = width/2 + cos(radians(angle))*radius;
    float vy = height/2 + sin(radians(angle))*radius;
    vertex(vx, vy);
    fill(angle, 100, 90);
  }
  endShape();

  theta += 0.0523;

  //if (frameCount % 2 == 0 && frameCount < 121) saveFrame("image-###.gif");

}