private void bounceOffSprite(int oneHitIndex, int otherHitIndex) {
   // Swap motion vectors for
   // bounce algorithm
   Sprite oneSprite = (Sprite) elementAt(oneHitIndex);
   Sprite otherSprite = (Sprite) elementAt(otherHitIndex);
   Point swap = oneSprite.getMotionVector();
   oneSprite.setMotionVector(otherSprite.getMotionVector());
   otherSprite.setMotionVector(swap);
 } // end bounceOffSprite()