+--------+
                         |   CR   |
                         +----|---+
                              |
                  |-------|--------|-------|
                  |       |        |       |
               +--|-+   +-|+    +--|-+   +-|+
               |BRAS|   |SR|    |BRAS|   |SR|
               +----+   +--+    +----+   +--+