Circle path

Rotor r;
float timer = 0;
int mode;

void setup() {
  size(1000,600);
  smooth();
  noFill();
  frameRate(60);
  background(255);

  mode = 1;
  r = new Rotor(random(width/2)+100,random(height/2)+100,random(40,100));
}

void draw() {
  noStroke();
  fill( 255,255,255, 10 );
  rect(0,0,width,height);
  noFill();

  float t = frameCount / 100.0;
  timer = timer + frameRate/1000;

  r.drawRotor(mode);

  if(timer > timeLimit()){
    timer = 0;

    if(mode != 1){
      //background(255);
      float newR = random(40,100);
      float newX = r.centerX + cos(r.angle) * (r.radius - newR);
      float newY = r.centerY + sin(r.angle) * (r.radius - newR);
      r.newPos(newX, newY);
      r.radius = newR;
    }
    mode *= -1;
  }
}

float timeLimit(){
  float timeLimit = random(50);
  return timeLimit;
}

class Rotor {

  color c;
  int thickness;
  float xPoint;
  float yPoint;
  float radius;
  float angle = 0;
  float centerX;
  float centerY;

  Rotor(float cX, float cY, float rad) {
    c = color(0);
    thickness = 1;
    centerX = cX;
    centerY = cY;
    radius = rad;
  }

  void newPos(float x, float y){
    centerX = x;
    centerY = y;
  }

  void drawRotor(int mode) {
    stroke(c);
    strokeWeight(thickness);
    if(mode == 1){
      angle += frameRate/1000;
    }else{
      radius += 2;
    }
    xPoint = centerX + cos(angle) * radius;
    yPoint = centerY + sin(angle) * radius;
    ellipse(xPoint, yPoint,thickness,thickness);
  }


}