It's not. In the case of this knot it's a fairly small size, and only so many certain combinations. None of which involve any exact pixel matches. The fact of the matter is when comparing the knot where it's a handful of pixels, they're as different as you can be.

Nothing here is even close to a rip, even the subject matter can't be argued for since they're not based on original content. It's a sailors hat and bandana, two hats that have existed long before Maple Story. So to clear up any confusion:

1) It's not violating copyrights because they're not copyrighted designs.
2) They're not ripped because the pixels aren't even remotely close. Ya, if you step back and look at them you'll think "ya they look alike" because they're based on the same real-life counterparts, but the pixels aren't similar at all.