Inside/Outside

Motorway Service Station I'm afraid, but there's not a lot else to photograph when you are travelling all day. I was intrigued by this picture though - trying to figure out what is reflected from outside and what we are looking in on. 

I realised that it would meet the Mono Monday Challenge - Angle, as there are certainly angles all over it, but then I was thinking it must depend on the angle of the glass and of the viewer as to whether you see through or get reflections or both.