Figure 2
E. Edlund et al., Phys. Rev. Lett. (2012)

Through the looking glass. These “snub hexagon” patterns are mirror images of one another (plus a rotation) and cannot be overlaid with any combination of in-plane shifts and rotations. These chiral patterns were generated by assuming a complicated but isotropic force between each pair of particles. (To see the difference between the two patterns, compare the triangle orientations in similar rows of six triangles in the two images.)