
1931: Someone had a great idea to put ads in the middle of Newton color disks (like these). Notice the combination of "high school science classes" and "package of cigarettes".

1933: Sales robots! Some guy hid phonographs behind cut-out cardboard dummies. Guess nobody could tell the difference anyway.

1934: Wow, something like this passes for emerging media even today. Person standing in front of a mirror triggers light that illuminates an ad layer behind the mirror's surface.

1936: Advertising mirror, perfected. Now with a phonograph record triggered by a light sensor.