The two groups were separated by an 'imaginary' line down the middle of the room.
an 'imaginary' world of dragons and unicorns
a child's 'imaginary' friend
(..) At least that's when his hallucinations seem to have begun. What are you talking about? What hallucinations? One, so far, that I am aware of. An imaginary roommate named Charles Herman. Charles isn't imaginary. They have been best friends since Princeton. Have you ever met Charles? (..)2001 A Beautiful Mind