Hold on, please, while I triangulate an answer to this. Currently, I'm going through writer's block, so I may need a team to help me work it out. I'm sure the answer is as old as the hills, and can be found in many parts of the world throughout various civilizations. It's no big sacrifice coming up with a response, not as long as the facts don't desert me, it's a jungle out there. ~
I guess you didn't get the memo: the world used to have a tree of life. It came down at some point, and tribes all around the world started building pyramids, all about the same time. In northern Europe they adopted trees of similar shape, and in some countries they tied ribbons to a pole to remember the shape of the tree of life.