Copyright infringement doesn't apply to original works made for free. It would only apply if you were to sell a product with the design and name "PPK".
Creative Commons License. you may use it, but not redistribute it or sell it without permission/Consent. Its a form of art just like any other.
[Edit] Sorry, Re-read the posts and figured out what you were talking about. but He has a Creative Commons license on it because it is art. (Creator loving read this)