Earlier I wrote about this crystal sculpture on the NTNU campus. It focuses sunlight onto metal plates, and on very sunny days it burns holes in the metal. I finally found the plates, hanging in the cafeteria inside the cafeteria in the Realfagbygget Building. Here is a picture of all of the plates, and a picture of the plate from the first year. The first plate has the most pronounced markings, as the crystal has been slowly getting pock-marked from the weather and the effect of the focusing is diminishing, making more recent plates not as interesting.