While the posted question didn't seem to have anything to do with genealogy, I think I can provide an answer with some connection to genealogy.
There was a disagreement between the Sages as to whether the mezuza should be placed horizontally or vertically. As a compromise, it was placed on an angle.
It should also be noted that, contrary to what was stated in the original posting, not all mezuzas are placed at an angle. This is an Ashkenazi custom. The Sephardi tradition is to place them vertically.
