Would you like to have rainbows in your home? These window clings look like clear plastic stickers in the shapes of cut gems, but they also contain diffraction gratings so that they will turn light from the Sun into shiny beautiful rainbows.
If you are interested, buy them from the Rainbow Symphony store. I am not affiliated with Rainbow Symphony and I won’t make any money if you buy these. I saw these when I was purchasing ISO compliant eclipse glasses and thought of the club.