When I was younger, one of the few things I enjoyed much at all was writing fiction.
I took a deep interest in grammar, spelling, and especially the nuances in meanings between similar words, the way two words with very similar definitions can evoke two very different ideas or pictures. To yell or to scream. To giggle or to laugh. Softly or gently. Angry or enraged. Jump or pounce. You can put exactly the picture you want into someone's head if you can find exactly the right words.
I was never all that good, and I haven't written in years, although it's one of those things I perpetually intend to do without seeming to find the time.
But I guess it has been sort of a signature on my life. So, I suppose my cutie mark might be a piece of paper with writing on it, or a pencil (or quill) and paper. Or a book with my name as the author.
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You don't need to hide, my friend, for I am just like you.