Recently I remembered something I had once done in my kindergarten days, namely creating a kind of window deco by melting colored plastic granulate into a surface that resembles glass, to get something reminicent of a stained glass window. If there is any more specific term than “window deco” for it, I beg you to share it with me since I have no clue what to call these “glassy, window, deco things” ;-)  
This collage is a little making-of of my first attempt after getting the materials. The first four images show how the differently colored granulate pearls are arranged in a metal form to create a pattern (of Rainbow Dash’s cutie mark in this case). Note the little wire ring among the pearls in the upper part of the pattern in the fourth image. That ring is to form an eye to hang up the final “glassy, window, deco thing”.  
Once the pearls are arranged they are put in the oven for a couple of minutes where the pearls melt to form a solid but transparent (except for the white) plastic layer.  
Finally the “glassy, window, deco thing” can be taken out of the metal form to be hung up or used in whatever decorative arrangement.