class Leaf {
  int x, y;  //the leaf's position
  PImage picture;  //an image object
  int rate;  //rate of waiting to be redrawn

  Leaf(){   //constructor
    x = int(random(width));  //get an initial location
    y = int(random(height));
    picture = loadImage("maple_leaf.gif");  //get the image
  }

int k=0;   //a counter 
  void draw() {
    if(k==rate){  //if the counter is as the rate then draw
      x += int(random(-5,5));  //random tremblings
      y += int(random(-5,5));
      k=0;  //reset the counter
      }
    k++;  //increate the counter; during every increment there is no draw 
      image(picture,x,y);  //now draw the image
    }
  }