Are CITY and Nichijou set in the same universe?


Recently, I've started reading _CITY_ , the manga that Arawi Keiichi started
working on after finishing _Nichijou_.

There are apparently some _Nichijou_ cameos in _CITY_ , such as this blue-
haired mangaka named ["Naganohara
Daisuke"](https://citymanga.wikia.com/wiki/Daisuke_Naganohara) who briefly
appears in chapter 25, and also this [book
cover](https://numahachi.tumblr.com/post/169861278609/ogi-confirmed) by
someone named "Ogi Wataru", which briefly appears in chapter 59.

Does this mean _CITY_ and _Nichijou_ are set in the same universe? Or are
these just easter eggs? Is there any other evidence, for example, word from
the mangaka, or perhaps any additional cameos?

