Hmmm. Not very hard, I guess. What I was heading for was a situation where the laser ends up being pointed at a bomb and you have to use a mirror to block the laser instead of reflect it. But then I remembered your earlier annoyance at the fact that there was a level you completed where the last thing it does is hit a bomb, and it still worked. Which makes my little trick useless, since it doesn't really matter if you hit a bomb, as long as all the bulbs light up. Oh, well.