Well, this ended up not being the post I thought I was going to make. I was going to say "the phrasal verb
fell over", but apparently that's not a phrasal verb for most speakers! Instead I'll say "the adverb
over, which implies the object's motion is somehow notably lateral".
The phrase "fall over" generally implies a subject which has an incompletely stable or completely unstable vertical position ("upright") and a more stable horizontal position ("on its side"). You can balance a pencil or an egg on one end, but it'll probably fall over quickly. A sufficiently wide cone is difficult to make fall over, if it's on its base. A
Weeble is essentially impossible to make fall over without modification. A sphere can't be said to "fall over"; it just doesn't make sense.
Because of this, things that fall over will generally land on their side, or perhaps upside-down. That's a physical observation rather than a grammatical one, though.
I specifically disagree with MuttQuad's example. The phrase
fall over the edge is a different construct from
fall over; the former is "fall" with a prepositional phrase "over the edge". There's nothing wrong with referring to a sphere or ball as having "fallen over the edge" (though I'd prefer something like "fallen off the shelf"), but even then I couldn't say that it simply "fell over".
Indeed. Good luck and best wishes.