note how the fencing can follow the contours of the ground - the feather edge boards are cut to size and the gravel board is cut with a jig saw to follow the ground.
Note also the D-rail has been brought down the front of the leading post.

The low fence was constructed in the same way, using feather edge boards cut into thirds and just 2 rails.
The main fence has 4 rails.

Here the fence follows the slope of the property.

gravel board still to be completed here