```goat

                          
                            +- Changed block
                            |
                            v
o o o o o o o o o o o o o * o o <-- physical blocks
| | | | | | | | | | | | | | | |
+-o +-o +-o +-o o-+ o-+ *-+ o-+ 
  |   |   |   | |   |   |   |
  +---o   +---o o---+   *---+
      |       | |       |
      +-------o *-------+
              | |
              +-* <- Changed root block
```