Just an illusion

Had to go and do a job at the School of Scottish Studies today.
George Square was once a lovely part of Edinburgh where many famous people lived. Unfortunately it's now home to many ugly buildings including my
workplace.
Thankfully the School of Scottish Studies is housed in one of the untouched buildings of the square. This is the floor of the entrance hall.

I hadn't realised until after I took it that this forms a bit of an optical illusion.