…Made from ethylene vinyl acetate (EVA), otherwise known as foam rubber, a pair of Unifold shoes don’t require molding, lacing, sewing, gluing, or any other advanced production techniques. You simply buy a pair and fold them up around your feet. Because Unifold shoes are easier to manufacture–you just cut a sheet of foam rubber into the proper pattern–they’re cheaper for consumers to buy, and as an added bonus, they can be shipped and stored flat en masse, further cutting down the price the end user has to pay for a pair. In fact, Unifolds might not even need to be manufactured. In the developing world, for example, Han suggests that a pattern could be downloaded and then brought to a local shop to be printed out.
Found on FastCoDesign