Wow... thanks for bringing this up, and nice photos, too!

For some reason, this brought me right back to high school art class, and "perspective drawing," where we had to place a dot somewhere on the paper and then draw an image-- street, ocean, roads, river-- all of which had to meet at that point.

Truthfully, hadn't thought of using vanishing points in the context of photography, hence the gratltude... now I want to go explore this a bit more!