The pins and coasters are made of 5 mm black Perspex and the holder of 7 mm transparent Perspex. The laser cutter uses the darker parts of the pictures to engrave. I used pictures in negatives, because the under layer of the black Perspex is white. I’ve chosen for this colors, because then you can see the black pins through the holder. I think this is very beautiful! You don’t have to glue the parts together, because the pins are connected with a tight fit in the holes at every corner of the holder. You only have to glue the circles at the bottom site of the holder.