This figure shows two abutting structured zones. Zone 1, on the left, is 17 by 9 by 7, and zone 2, on the right, is 7 by 9 by 5. The entire j-max face of zone 2 abuts the larger i-max face of zone 1. The grid point (17,3,1) in zone 1 coincides with the grid point (7,9,5) in zone 2, and the point (17,9,5) in zone 1 coincides with the point (1,9,1) in zone 2.