=================================
|   A   |   B   |   C   |   D   |
=================================
|  a1   |       |       |       |
|_______|_______|_______|_______|
|  a2   |       |       |       |
|_______|_______|_______|_______|
|  a3   |       |       |       |
|_______|_______|_______|_______|
|  a4   |       |       |       |
|_______|_______|_______|_______|
|  a5   |       |       |       |
=================================