Quasicrystals are one of those topics that I've always been intrigued by, but never had a chance to really investigate. (Quasicrystals are materials with aperiodic ordering: x-ray diffraction shows that they have internal symmetry, but they lack the translational symmetry that true crystals have.) Now they've given me a reason to find the local engineering library: work to be published in the Journal of the American Mathematical Society shows that the standard equations used to calculate electrical conductivity don't work for quasicrystals. The very idea makes my head hurt if I think about it too much. Clearly one for the research file.