The Gecko's feet stick to surfaces through simple van der waals forces. The physics is simple, but the execution is quite difficult; the gecko accomplishes this feat using hair-like structures on their feet that split into small and flexible branches that are only 200nm thick. John Main, of the defense sciences office at DARPA, points out our current technology cannot easily replicate these structures; however, we can still use our technology to replicate the result. This has been done, in the case of gecko feet, by micromachining a vast array of shapes into materials to maximize surface area contact and van der waals forces. I mention this because it made me think of the vast array of miraculous technologies that nature achieves every day; how plants can convert sunlight to chemical energy and consume carbon dioxide in tandem, how starfish regenerate limbs, or how an octopus changes color to blend in with its environment; the list goes on. We need not necessarily reproduce the structure that these lifeforms use, but we can still replicate the results in our own way.