By request.
Beware: IT'S MASSIVE.
The tutorial:
Part One - Making the Box
Part Two - Making the Sig
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There were going to be three parts, but my Photoshop kept crashing on me. L.O.L. Probably because the tutorial is so big. Part two looks different than part one because I wound up making it in Inkscape.
If you are actually going to attempt to do this, here's what you'll need:
These images (already cleaned up for you

):
Red Yoshi block
Yellow Yoshi block
Green Yoshi block
Fat Shy Guy
Red Yoshi
Green Yoshi
These Shapes:
Twirly Shapes
These Brushes:
Scratchy Brushes
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Just a few other things.
I do not explain everything in full detail. I pretty much say what you need to do and provide a picture - I don't go through every minute step like in my other tutorials.
I am using CS2. Older version users not be able to do some of the steps.
If you need help or need me to elaborate, just ask.
Have fun.
(This took forever to make XD )