I think it's the walls nd ceilings one
Answer:
Go and click on the invitation bar and you can find an option written as " search friends ". Then it's easy to find that unknown user if you're pretty fond of his/her username and DP ( display picture ).
Explanation:
i asked a friend and we came up with this answer i don't know if it's right I've never tried to look up someone so try it out and see if it works if not ill try again
<span>to sacrifice self-interest for the common good</span>
