Personally, I can't see the answer being "yellow", as this is all about nouns and tangible objects (like things and animals).
Having said that, I enjoyed how the case was built on the faded outline, while this entire spot of the ball shows faded black print, as may be observed by the outlines of the infamous "Y".
(I'd rather opt for the "yxa" approach, probably the route taken by someone just browsing image search for quick ideas and failing to realize that this is not an English word. — Non-indo-european languages and scripts do exist.)