That top answer is hardly conclusive - it's definitely a possibility, but given the weird choices in the art for the "axe" (bendy handle, not a defined edge at the bottom) - I buy it could have been a yellow paint tube.

Nouns beginning with Y are not exactly easy to come across (the official "Yo-Yo" is hardly as common as the other words on the ball), and as has been pointed out, it's entirely possible the art was worked on by multiple people and changed or whatever.

Maybe the wrong-language thing is more likely (the U-boat choice is the thing that makes me lean this way the most), but I don't think the yellow paint tube idea is completely impossible.