The Secret Entrance & The Spacious Interior
The Sewer System (Pee into the black tube located INSIDE the fort (Top Picture) -- it drains out through the buried line to the outside.
(Bottom Picture.) Pretty ingenious, but when I found out it's purpose, I disallowed it's use due to obvious reasons.
The Raincatching System -- Catch the water thru the flashing in the First Picture; it flows through the pipe in the Second Picture; and collects into the can in the Third Picture. Handy for pouring down the sewer system that Mom won't let Reed use.
Accessorizing the inside -- a handy table/raised bed in the First Picture. And a shelf for holding valuables like balls and trophies. Notice the blue egg in the center -- decorated like a grenade... it's been there for two weeks and Reed says it hasn't started to smell ??? Any predictions on this boy's future profession? Gotta love him.