When I was 10 I started to regularly go (after school) to an Olivetti store in my hometown, just hanging there with the owners, that would teach me a few things, like how to enter the M24 bad sectors in the BIOS, or how most mechanical writing machines could be "fixed" just by cleaning them. Such machines were so well designed: the best industrial designs of the time. I was already an owner of an Olivetti PC1, probably the strangest MS-DOS machine of that time... Anyway talking about all that I just remembered that the owner had a very odd sense of the humor. One day a customer, that loved to develop the films and print his photos at home, told that he had always issues with the leaky window that would let too light enter his black room. Then the owner told him, are you serious? Now they sell the "black light bulbs" that will suck all the light, and indicated the store, in Canicattì (near Campobello, my home town), and that if he would hurry, there are still the last pieces available. The man jumped into the car to immediately go get a few black light bulbes.