There is a point where the shade of blue stops and the shade of green starts.<quoted text>Not true at all. Have you ever seen a color wheel? At what point exactly, does green become blue?
That's how evolution works. The difference between each element and its predecessor is minute. But over many generations, blue could become red.
Say you are ten feet from a brick wall and every second to move half way to the wall. When do to touch the wall?