point of clarification: quasicrystals are by definition non-periodic, most known examples of which are metamaterials. the first sentence incorrectly ignores a v

point of clarification: quasicrystals are by definition non-periodic, most known examples of which are metamaterials. the first sentence incorrectly ignores a very interesting class of engineered compounds. http://en.wikipedia.org/wiki/Quasicrystal http://en.wikipedia.org/wiki/Quasicrystal