A unit cell, bounded by dashed lines, is shown in violet.
Arrows depict site displacements for the zone-center (i.e., zero wavenumber) .
32 and 36, but because it is not rigid with respect to changing the unit cell size, it is not strictly jammed.
To understand the origin of the differences in the zero-mode count for different boundary conditions, we turn to an elegant formulation (2) of the Maxwell rule that takes into account the existence of redundant bonds (i.e., bonds whose removal does not increase the number of floppy modes; ref.
The physics of systems as diverse as architectural structures, network glasses, randomly packed spheres, and biopolymer networks is strongly influenced by a nearby isostatic lattice.