wow Akira that's amazing at age 7. I can hardly believe you did that at that young age. I was reading a book a long time ago called "drawing on the right side of the brain" the best art instruction book i have ever read, i recommend it to anybody. somewhere in there it was talking about the development's of childrens' brains and perception, and it said at around age 12, artists start to develop the geometrical perception and stuff and start to draw humans in correct form, and objects in the correct size compared to another. at age 7 thats impressive.