HexBeam is a data generator used for testing the FEI. It generates data that represents a cube of hex elements. More precisely, it's a cube that can be elongated in one dimension, forming an arbitrarily long 3D bar. The dimensions of the bar are WxWxD. In parallel runs, the bar is divided such that each processor has roughly D/numprocs "slices" each with WxW elements.
The slices that are separated by processor boundaries share common nodes, which are "shared nodes" in the global mesh.