This is an Iguana cage that my daughter Andree-Daniele (aka Andrea) asked me to design for her. The top comes off for big time cleaning and the square openings in the top are all covered with heavy screen and hinged to be opened as little doors for changing water, feeding and light house keeping. The three Plexiglas panels are all the identical size for easy replacement and just slide down into the grooved sides of the uprights. When in place, the lid encloses and supports the upper structure. The triangle opening is covered with plexiglas and is transparent.