OH BOY!
This is a letter that I have been dreading.
It was written in two passes one on top of the other. The first was
with the paper in the normal "portrait" position, then it was rotated
90 degrees and written over the first script, with it in the "landscape"
position.
This was done to conserve paper and I don't believe it would have been
so hard to read, if the ink hadn't been badly faded.
When you become aclimated to it, you are able to ignore the verticle
script and read just the horizontal script . . . fairly well.