I would just use 50/50 or gum paste and make a round , flat slightly tapered bottom and cut a a square. Made a small tassel to hang off the side using fondant.
Sending you this link. Read what spooky_789 has to say. click on graduation cap and then click again. you will see what she is talking about I am going to make this same cap for my grandson. Actually, made it last week. got to put it all together. htl use the styrofoam egg and do exactly as it says.
http://www.wilton.com/forums/messageview.cfm?catid=8&threadid=163103
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