The closer building looks larger than the farther one, but it's just an 'optical illusion'. The two buildings are actually the same size.
She had/harbored no 'illusions' about how much work the project would require. [=she knew the project would require a lot of work]
The video game is designed to give the 'illusion' that you are in control of an airplane.
(..) you were strong. Oh... I am filled with doubts. And I've begun to believe that being firm and strong was the illusion and that I am unsure now because it is the most honest way to be. Not in the face of a great heathen army (..)2017 TvShow: Vikings Title: Revenge Season: 4 Episode 18