A new representation of topological defects in smectic liquid crystals that captures both broken translational and rotational symmetry. B.G. Chen, G.P. Alexander, and R.D. Kamien, Proc. Natl. Acad. Sci. USA 106, 15577, doi: 10.1073/pnas.0905242106 (2009).

Image courtesy: Dr. R.D. Kamien, University of Pennsylvania, designer - Bryan Chen.