You are right.. this is a iron rods - around the swimming pool. in the bg, you see some bush and apartments doors.
Also, the oatmeal box is cardboad box. which is spray painted inside and covered with black contact paper. The lid is spray painted and on top a black paper taped. Still dont know where could be the light leak...
About the back side of paper ... I m going to do a test on it, maybe this week end.
You guys have been of great help.
Thanks a ton...