Scores of people will walk right by an artistically decorated store window without giving the display a glance. On the other hand, another store window with a novel display catches the eye of every passer-by.
An unusual novelty, particularly if it is puzzling and mysterious, will attract and hold more attention than a $100,000 painting by a 16th century master.
The reason for the attraction is this: Movement always arrests the eye. Herewith is described a window display novelty which always commands attention. Not only once, but time and again. It consists of a device suggestive of the ever elusive phenomenon: “Perpetual Motion.” Unlike many of the so-called “perpetual motion machines,” it has no gears, belts or levers. It consists simply of a polished steel ball rolling “perpetually” around a circular track.
Suspended above the track is what appears to be a huge permanent magnet, which is for illusory effect only. The device makes a very puzzling illusion. The ball rolls about 30 miles in 24 hours, while an indicator records the mileage. Passers-by will pause time and again to see how many miles the ball has traveled...
(later) ... the mileage indicator is mostly for psychological effect, but may be dispensed with. Curious passers-by will stop daily to see how many miles the ball has traveled. New signs will greet their eyes. With very little trouble, a mileage indicator from a bicycle can be remodeled to serve the purpose.
This “perpetual motion machine” compels intention. It is an excellent advertising attraction for any store window. Few passers-by are artists; every passer-by is curious.
The device will attract considerable attention to any display or signs set up in your window along with it. While watching the ball their eyes will fall on the signs.
“Perpetual Motion” Machine Makes Novel Window Display
(Modern Mechanix. July, 1931 : full article here )
