  Systems of hard shapes crystallize due to entropy. How is entropy distributed
among translational and rotational microscopic contributions? We answer this
question by decomposing thermal fluctuation of crystals of hard hexagons into
collective modes, a generalization and quantification of the Onsager picture of
hard rod liquid crystals. We show that at densities both near densest packing
and near the solid-hexatic melting transition, solids of hard regular hexagons
hold most of their entropy in translational degrees of freedom.
