Adsorption of crystals of a chiral biological molecule onto a gold-coated cobalt surface. It can be seen that larger crystals of a specific form of the biological molecule (left) tend to accumulate on the surface rather than its mirror image (right). While the crystals on the left reach a height of about 1.2 nanometers, on the right they do not exceed 0.8 nanometers. The physical advantage of the left form in accumulating on the magnetic surface ensures that in competition with its mirror image, it would establish itself as the "winning" form.