When I was small my Father did a lot of ice fishing. At that time we were pretty close to broke, so he had made himself a wooden ice fishing hut.
I am unsure of the exact measurements at this time. Because when you are small, the scale of things is altered and defined by your own size. The shed must have been about 3 feet by 8 feet, made out of simple framing and plywood. The exterior painted white. The interior was unpainted, and on the foor were 6 round holes, which my Father had made covers. There was a door with simple hinges, and one square, and small window.
I spent a lot of time in the summer, in the ice hut. A lot. I played school in it, with all of my best dolls. I would spend hours dragging chalk boards, and books, and chairs all of the way across the green lawn. I also had a library in there for a while, and I had spent weeks making library cards and convincing my mother I needed a black ink pad so I could stamp the cards with a pencil eraser dabbed in black ink.
It was a an animal hospital for some time. My stuffed animals were much better patients than any live animal I could convince to enter.
I enjoyed all of that "alone" time, and it is something I doubt my children will ever know. Solitude, or freedom. It is doubtful at this time, that I will ever send them out alone or unattended to our own backyard. No. That will not happen. An afternnon on a bicylce, riding in the sun jumping curbs alone. That feeling of having change in your pocket, and going to get a snowcone ALONE. It just is not going to happen.