That purple fan is beautiful. Like the matching cord used.
Back around 1974 I visited one of my friends, whose mother was having the kitchen of their circa 1900 home renovated at the time. While I was there, we tore off some "Congowall" material from between the countertop and upper cabinets. When this was removed, an electric socket - like the ones shown above in 3beltwesty's post - was revealed. They had always wondered why there was a slight bulge in the wall at that point, and now they knew why. My friend got a standard light bulb, and screwed it into the socket; it lit. The electrical device had been covered up since at least the late 40's - early 50's when the kitchen had last been remodeled. They found another such socket on another wall, but missing the brass cover plate with lid. His mom said when she was young, many houses had that type of outlet.
Somewhere I have one of the screw-in plugs like shown on the purple fan. It is marked "Benjamin", and I have no idea what it came off of. It was always in our junk box when I was a kid, and used to have a couple inches of green cloth covered twisted-pair cord sticking out, but I removed that.