As Cassidy is seeing his room trashed a black and white checkerboard print is seen on the wall; this is Kandinsky's 1937 painting 'Thirty' and is hung upside down.
SPOLIER:
Cassidy is sitting at the edge of the skyscraper . As Fitz further approaches you can (barely) a see the safety cord attached to him. (top right corner, bird's-eye view)