Anyway, I came across a pose called the supported shoulder stand. Although the first picture I found (in a book) shows the legs angling about 45-degrees over the head.
And I remembered that when I was a kid I would often sit in that pose because it felt good.
So I must be some natural-born yogi! Just kidding.
It makes sense that a person would be able to find some of these poses on their own though, they just feel good!