  Nanoparticles with "sticky patches" have long been proposed as building
blocks for the self-assembly of complex structures. The synthetic realizability
of such patchy particles, however, greatly lags behind predictions of patterns
they could form. Using computer simulations, we show that structures of the
same genre can be obtained from a solution of simple isotropic spheres,
provided control only over their sizes and a small number of binding
affinities. In a first step, finite clusters of well-defined structure and
composition emerge from natural dynamics with high yield. In effect a kind of
patchy particle, these clusters can further assemble into a variety of complex
superstructures, including filamentous networks, ordered sheets, and highly
porous crystals.
