When most folks think of improving the design of a flashlight, they think of making it brighter or smaller. It's easy to overlook the average flashlight's central flaw: They emit a limited, circular patch of light that doesn't really jive with human peripheral vision.
On a trip upstate last year, I was looking for my runaway dog in the woods at night. While my LED flashlight was powerful enough to cast a far beam, having to trace that small circle of light over a wide swath of trees felt like painting a battleship with a toothbrush.
I'd have done better with a Morphalite flashlight, created by product developers Frank and Gary Wall. They've figured out how to create a lens that effectively refracts light into a 180-degree arc, enabling the user to scan a large patch of horizontal darkness in one go. Alternately one can rotate it 90 degrees and send the spread vertical, to better illuminate a trail one's walking down, for instance.
The Walls' DIY video below is, well, DIY quality, but that doesn't detract from the cleverness of the product's design, and their logic is unassailable:
Interestingly enough, engineer Frank discovered how to create the lens purely by accident. You can read the tale here.