Oh — Did I say that you needed to put glass in front of a white wall for it to look good? Well, not exactly. These yellow wall pieces by Robert Kaindl look spectacular against this black wall. Here's why: They have a high percentage of opaque glass in them. The black wall shows through the translucent areas adding contrast with the opaque yellow which shows up well against the dark wall.
So as a rule of thumb: if you are placing a piece of glass that is all or mostly translucent, the colors are going to show up better in front of white and with light coming from behind it. But if the glass is mostly opaque, then you can put it in front of any color wall and light it from the front.