The woman at left might look like she’s been hypnotized, but she’s actually just listening to a particularly interesting radio program, thanks to the whole-house headphone system described in the March 1943 issue of Popular Mechanics. Twisted lamp cord is carefully run through the walls, to open-circuit headphone jacks in whatever room they are desired. In the living room, the wiring is connected to the radio, and the magazine provides details on how to tap in.