Ok, since slowglue is bent on making fun of me (that coming from the inventor of "flashlight bears"

, and since the morning has passed, here is the answer.
This shot was taken at night. It was pitch black (mostly)
What do you need to take this shot:
(1) two building standing side by side, with windows turned towards each other.
(2) a lamp
(3) a curtain
(4) (correctly posted by slowglue) a camera
It is a reflection, but it's reflection of my window in the window of the building across. So, in that, you are correct, didwest.
I metered to one of the bright lights on the street, locked the exposure, recomposed, with the reflecting window in the middle of darkness, and shot away.
The culmination of this picture-taking exercise was something being thrown by the residents opposite, a baby crying really loudly, and a bunch of pigeons hitting the railings of my balcony.
Anyways, not meant to be pretentious - just a puzzle for the morning.
Thanks to all for looking.
Gleb