int numBalls = 100;
BG main = new BG(100,50);
Ball[] b =new Ball[numBalls];
int freq = 0;

void setup(){
  size(600,400);
  smooth();
  for(int i=0;i<numBalls;i++){
   b[i] = new Ball(random(width),random(height));
 }

}

void draw(){
    main.drawBG();
    for(int i=0;i<numBalls;i++){ 
      b[i].move();
      b[i].display();
      freq++;
      if(freq % 3 == 0){
        b[i].change();
      }
    }
    
  
  
}