  We investigate Thomson's problem of charges on a sphere as an example of a
system with complex interactions. Assuming certain symmetries we can work with
a larger number of charges than before. We found that, when the number of
charges is large enough, the lowest energy states are not those with the
highest symmetry. As predicted previously by Dodgson and Moore, the complex
patterns in these states involve dislocation defects which screen the strains
of the twelve disclinations required to satisfy Euler's theorem.
