You guys really didn't know about the bush/cloud thing? I'm not bragging (because I guess it's self-insulting), but I've known about that fo-ever. Wish I would've just mentioned it, geez.
Here's how I first noticed it: as a kid, I always saw Mario with the moustache in the artwork of the manual and on the cartoon. It was his trademark (more so than his big, round nose, in my opinion). Well, that made me start seeing moustaches on the clouds. And finally, because I really started paying attention to the clouds, I thought, "What else might be like Mario?" And of course, I examined the bushes and found them to be exactly the same shape as the clouds.
Has anyone ever paused the game while Mario has the star power? I always thought it was so interesting. I realized even back then that Mario and Luigi were identical except for color. So, seeing Mario turn different colors because of the star power made me think, "Damn, there's more than just Mario and Luigi in here!" So, I gave all the color combinations a name (non-Italian names, by the way, because I wasn't that clever) and sent a letter to Nintendo demanding that their true identities be revealed and that they get their own games. :lol