Conservatory Roof Illusion

This photo was taken during a performance of the play Stella by Starlight written by Irish playwright Bernard Farrell and performed by Craic Theatre Productions.

The roof of the conservatory appears to sometimes recede away and then sometimes project forward in an ambigious manner similar to the Necker Cube illusion

The ambiguity is amplified by the stage lighting which is hitting the underside of the roof giving a perspictival dimensional cue reminiscent of the Penrose Triangle and Mach's Corner visual illusions.