Funny, I think on a different picture I uploaded somewhere (I think not here, though) someone commented he only likes 6x7 format pictures if they are vertical. Anyway, I don't know if vertical pictures are more difficult to take. In case of this picture I took horizontal as well as vertical shots but I just liked the vertical ones much better. Could be because the window and the x-rays are of a similar aspect ratio than the whole photo.

This little discussion here reminded of something I once read in a book by Jeanloup Sieff, I looked it up. The author in conversation with Robert Doisneau:

"JLS: Is there a phallic symbolism in the vertical composition of the image, in contrast with that of self-abandon in the horizontal plane?
RD: Disturbing choice, the virile or the lascivious, the obelisque or the odalisque. Ah, but what a context for the leaning tower of Pisa!"

Something to ponder, people!