[piasa]

Left-handed writer’s writing slants upward, unlike the writing on the anthrax letters. That is, if it slants at all.

[Aliska]

Mine tends to slant downward if it slants at all. My sister & I both are left-handed, as was our mother. Her writing doesn't slant, but mine often does downward, esp on unlined paper.

A possible explanation is that I don't write like so many other left-handed people I see because my teacher taught me to turn my paper the opposite of what right-handers are taught, so I never wrote with my hand curved which looks awkward.

Maybe a better question might have been, "Why does the printing slant?" I don't know if there is any significance to it or not or whether it was done on purpose or not. Probably none whatsoever compared to the rest of it.

I've been reading more on it this am, fear we'll never know for sure like so much else.