neighborhood block schemes

This layout has three types of U-shape courtyard neighborhood block schemes.  Scheme A (top left and bottom right) is the most dense of the three with 34 units, one larger courtyard and a smaller courtyard.  Scheme B (top right and middle left) has 29 units and one big courtyard space.  Scheme C (middle right and bottom left) is the lest dense with 27 units and possibly two courtyards.