Disclinations are topological defects because they cannot be created locally by an affine transformation without cutting the hexagonal array outwards to infinity (or the border of a finite crystal). The undisturbed hexagonal crystal has a 60° symmetry, but when a wedge is removed to create a 5-folded disclination, the crystal symmetry is stretched to 72° – for a 7-folded disclination, it is compressed to about 51,4°. Thus, disclinations store elastic energy by disturbing the director field.