x_scale, y_scale... just don't know how, ow where to look

hi there
i want to use the technique, like this site:

(x_scale, y_scale) i am not that great in scritping, i can understand what they are doing, but not come up with something mysef…

is there any tut. or a fla. file which i can download or view, in order to understand this technique of transforming shapes smoothly…

best regards
melvin lardenoye