4 5 6 | Apr.
=========+=================================================+=======
July. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
Apr. | 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 |
---------+-------------------------------------------------+-------
July. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
Apr. | 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 | May.
=========+=================================================+=======
Aug. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
May. | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
---------+-------------------------------------------------+-------
Aug. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
May. | 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 | June.
=========+=================================================+=======
Sept. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
June. | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
---------+-------------------------------------------------+-------
Sept. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 |
June. | 24 25 26 27 28 29 30 1 2 3 4 5 6 7 | July.
=========+=================================================+=======
Oct. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
July. | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
---------+-------------------------------------------------+-------
Oct. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
July. | 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 | Aug.
=========+=================================================+=======
Nov. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
Aug. | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
---------+-------------------------------------------------+-------
Nov. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 |
Aug. | 24 25 26 27 28 29 30 31 1 2 3 4 5 6 | Sept.
=========+=================================================+=======
Dec. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
Sept. | 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 |
---------+-------------------------------------------------+-------
Dec. | 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
Sept. | 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 | Oct.
=========+=================================================+=======

Supposing the upper figure in each pair of horizontal line