0        1        2        3        4        5        6        7
0   *    0   *    0   *    0   *    0   *    0   *    0   *    0
|--------|--------|--------|--------|--------|--------|
|               A1    A2    A3    A4                  |
|             B1      B2      B3      B4              |
|           C1        C2        C3        C4          |
|         D1          D2          D3          D4      |
|       E1            E2            E3            E4  |          
-------------------------------------------------------
0        1        2        3        4        5        6        7
0   *    0   *    0   *    0   *    0   *    0   *    0   *    0