How is padding-top as a percentage related to the parent's width?

Question

Here is an example:

http://jsfiddle.net/QZAd8/1/

Notice how all of the red divs are the same height and have padding-top:100%;, yet

Answer 1

Just because it's the way it is suppose to be :) http://www.w3.org/TR/CSS2/box.html#propdef-padding-top