Second family becomes first to affix a mezuzah on executive home.

[Mosby]

1. Slanting the mezuzah is an Ashkenazi tradition

Mizrahi and Sephardic Jews mount it vertically.

I only know this because I live in a neighborhood with a ton of Jewish families, so at some point I looked it up.

Eta - in case anyone is interested, the important part of the mezuzah is not the case, its the klaf, which is a piece of parchment hand inscribed with Deuteronomy 6:4-9 and 11:13-21. The case can be anything, but often it has the letter "shin" on the outside, which represents one of Hashems names. On the back of the klaf there is the name שדי‎, (shaddai) which is the same name for Hashem on the case.

2nd edit - Hashem is a Hebrew term for God. Literally, it means "the name."