...............................
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............A...............
...............................
...............................
...............................
...............................
.CCCCCCCCCC.........DDDDDDDDDD.
...............................
...............................
...............................
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............B...............
...............................