Why did Kishi draw the One Piece symbol in the last page of the last chapter of Naruto?


Why did he put a One Piece skull and crossbones (along with the straw hat) on
the very last page of the last chapter of Naruto? Seems odd, as the authors
differ in both manga (Kishi - Naruto, Oda - One Piece), and I don't understand
why.

![enter image description here](https://i.stack.imgur.com/Uu5OE.jpg)




Oda also made a reference to Naruto in the latest chapter (766):  
[![One Piece
766](https://i.stack.imgur.com/sXkG8m.jpg)](https://i.stack.imgur.com/sXkG8.jpg)  
Notice Nami's dress with Konoha's symbol on it, and how there's a fox eating
ramen with a whirlpool on its back.

It's just a way for them to acknowledge each other's work.




Oda also made a reference to Naruto in the latest chapter (766):  
[![One Piece
766](https://i.stack.imgur.com/sXkG8m.jpg)](https://i.stack.imgur.com/sXkG8.jpg)  
Notice Nami's dress with Konoha's symbol on it, and how there's a fox eating
ramen with a whirlpool on its back.

It's just a way for them to acknowledge each other's work.

