  The rich variety of densest columnar structures of identical hard spheres
inside a cylinder can surprisingly be constructed from a simple and
computationally fast sequential deposition of cylinder-touching spheres, if the
cylinder-to-sphere diameter ratio D is within [1,2.7013]. This provides a
direction for theoretically deriving all these densest structures and for
constructing such densest packings with nano-, micro-, colloidal or charged
particles, which all self-assemble like hard spheres.
