COUPLERS constructed from FOUR +MITES and FOUR -MITES
BCE FACES: 4 + and 4 - OBVERSE / NONE ON REVERSE
4 +MITES and 4 -MITES
OBVERSE____REVERSE
This is a unique coupler because it represents extreme parameters in classifying RD packings according to the number of BCE Bmod faces (0 to 48) on the rhombic surfaces.