protected void mover(){
        if (Greenfoot.isKeyDown("up")){
            move(2);
        }
        if (Greenfoot.isKeyDown("down")){
            move(-0.5);
        }
        if (Greenfoot.isKeyDown("left")){
            setRotation( getRotation() - 1 );
        }
        if (Greenfoot.isKeyDown("right")){
            setRotation( getRotation() + 1 );
        }
    }