int nelements = 4;
  MyElement [] e = new MyElement[nelements];
  
  void setup(){
    for(int i=0; i<nelements; i++){
      e[i] = new MyElement(i, e);
      e[i].xspeed = random(1);
      e[i].yspeed = random(1);
    }  
  }
  void draw(){
    background(200);
    for(int i=0; i<nelements; i++){
      e[i].collide(); 
      e[i].move();   
    }
  }
  
  void mouseDragged(){
    for(int i=0; i<nelements; i++)
      if(dist(mouseX,mouseY,e[i].xpos,e[i].ypos)<20){
      e[i].xspeed = mouseX-pmouseX;
      e[i].yspeed = mouseY-pmouseY;
    }
  }