Board Thread:Questions and Answers/@comment-26388723-20151117064538/@comment-27148615-20151117121238

It does seem strange, now that you think of it. For Kirito, he may have chose clothing that was similar to his Blackwyrm Coat, black, has white lining, etc. As for Sinon and DDA, it could possibly be a coincidence, or as you describe, a design well liked by artists.

Also, it does look ridiculously similar to the holes on a bowling ball.