The way the light bounces around inside the piece of plastic depends on the angle you are looking at it. From right above only the sides of the plastic show up in blue. From the edge of the plastic the effect is more dramatic, but I think the piece could really use another LED in there somewhere.
From these angles we saw the best results of our little Glowy Geforce mod. The entire piece of plexiglass lit up giving the card a rather cool blue appearance over the heatsink.
Mounted on the MSI Ti4200 you can see how the light from the blue LED plays on everything. Personally, I was hoping for a more even distribution of light, but I guess it would be rather difficult to light the entire block of plexiglass evenly, all the way around.
This picture has the best effect of any of them, and as you can see from the side shot the card does look kind of cool in the position you would see it in a computer. When it was all said and done, the Glowy Geforce 4 attachment only took about 45 minutes from start to finish, and looks pretty decent. A fun mod for sure, and I think there are a few more things which can be done along these lines if you get really creative!