Algodoo

I like this one better than your previous version.

Btw -- I was wondering if you knew about this Algodoo behavior that I recently discovered (it has nothing to do with this particular scene of yours). Here's the setup: Create a very simple scene with any geometry (let's use a box for this demo) and a laser. The laser beam does not necessarily need to hit the box. Then right-click on the box and then hover down to the Material panel and make note of the Refractive Index value. Then close that panel and go over to the laser and delete the laser. Then go back to the geometry as before, and make note of the Refractive Index value again. YOU CAN'T, because it's no longer there! Apparently, Refractive Index only shows in the Material list when there is at least one laser in the scene. Now, if you were to open the Script Menu of any geometry, you would still see refractiveIndex in the list of events and variables. It's only the Material panel that displays Refractive Index when a laser is included in the scene.

Did you know about that? I discovered it just a couple of days ago.

Q: Did you know about that?
A: Yes AND no. Yes, I did notice that refractive index does not show up in the material panel unless there is a laser. No, I didn't know that refractive index is always on the script menu.