This structure is the same as the P-surface I posted yesterday. Chuang made the other one a long time ago with 4mm beads. I have tried to remade just one unit cell of this structure with 6mm beads (with the all of necks included) last night. Unlike the true P-surface which divides the 3-D space into two congruent regions, the two disconnected regions in Pseudo P-surface are not identical. In this structure, we used heptagons (blue beads) to simulate the region with negative Gaussian curvature. The neck region in this structure consists of hexagons (rings that contain white beads).