Before                          After
     Block 6                        Block 6
    Segment 1                      Segment 1
+----------------+             +----------------+
| Header         |             | Header         |
+----------------+             +----------------+
| Permanent 1    |             | Permanent 1    |
+----------------+             +----------------+
| Permanent 2    |             | Permanent 2    |
+----------------+             +----------------+
| Permanent 3    |             | Permanent 3    |
+----------------+             +----------------+
| Empty          |             | Tentative      |
+----------------+             +----------------+
| Permanent 4    |             | Empty          |
+----------------+             +----------------+
| End-of-segment |             | Permanent 4    |
+----------------+             +----------------+
.                .             | End-of-segment |
.                .             +----------------+
.                .             .                .
+----------------+             .                .
| End of block 7 |             .                .
+----------------+             +----------------+
                               | End of block 7 |
                               +----------------+