private void bounce(Actor a) {
        // reflect opposite side
        changeY = -changeY;
        // refelcts depending on incoming angle
        int reflected = getX() - a.getX();
        // caculate angle of reflection based on incoming angle
        // divide by 8 to minimize the rebound magnitude. Not as dramatic/hard.
        changeX = changeX + (reflected/8);        
        if (changeX > 7) {
            changeX = 7;
        }
        if (changeX < -7) {
            changeX = -7;
        }
        // sound effect
        Greenfoot.playSound("laser.wav");
    }