class Ladder extends Twofer{
  PImage img;
  Ladder(int px, int py){
     super(px,py);
     if (y == GRIDSIZE/2 || y == GRIDSIZE/2-2) {
       img = loadImage("ladder_h.png");
     } else {
       img = loadImage("ladder_v.png");
     }
  } 
  void draw(){
    image(img, (x * SQUARESIZE)-3,(y * SQUARESIZE)-3);
  } 
}

void addLadders(){
  ladders.add(new Ladder(GRIDSIZE/2, 0));
  ladders.add(new Ladder(0, GRIDSIZE/2-2));
  ladders.add(new Ladder(GRIDSIZE-2, GRIDSIZE/2-2));
  ladders.add(new Ladder(GRIDSIZE/2, GRIDSIZE-2));
 
}