For my class, I named it Identity Writing because we talked about how a fingerprint is used to identify someone just like traits of a person can be used to identify someone. We're sharing pieces of our identities in more than one way with these!
With my kids, I went around and colored everyone's thumbs with a washable marker (I was out of inkpads somehow). Then, everyone stamped their thumbprint into the top left corner of the paper. They used their prints to as a map of how to write their text. Now- they're third graders so they aren't perfect. (Mine isn't either... I'll claim it's because I'm still in third grade, too.) We added colors to special words and used lightly shaded pictures to add illustrations to our pieces.
All in all though- it was a pretty fun activity! Here's mine and I'll add pics when they're finished with theirs.