A stand behind B and same time B also behind of A, How can that possible ?

A stand behind B and same time B also behind of A, How can that possible ?

A, B के पीछे खड़ा है ठीक उसी समय B भी A के पीछे खड़ा है, यह कैसे हो सकता है ?

Answer :-  If both stand same place but there face are opposite side. in this condition A behind of B and B also behind of A. see in picture.