A few years back I came across a few "Hold to Light" Postcards of the 1904 World's Fair. I was amazed at the craftsmanship of these souveniers people sent through the mail. To make them work, the printer die-cut the up to dozens of openings into the cardstock to feature windows, ripples in water as well as the moon. Sandwiched between the die-cut layer and the printed back, colored tissue paper gave more detail to the cards.
Hope you enjoy the show!