quick simple design solutions

I love simple design solutions.  I came across this one in Key West, Florida.  As I was purchasing coconut juice form a mom and pop style convenience store/ kitchen, the water bag over my head right across the cashier grabbed my eye.  A light was shining directly on it, and I could see only a penny resting at the bottom inside the clear plastic bag filled with water.  I wonder what it was and asked the cashier.  He told me it is the easiest solution to get rid of flies.  This got me even more interested.  He said flies have many eyes, by directing a light on the bag, and making sure the environment has objects with different colors you can thereby drive flies away from the area.  Sure enough the surrounding objects had a mix of cool and warm colors, and the copper penny added more to the spectrum array of colors which made the flies avoid this shop.

Definitely a million dollar idea.  He told me a Haitian man suggested the water bag with penny idea to him to get rid of the flies. It is apparently an all natural fly repellent used by Haitians for centuries.