These tops depict a miniature garden. Hiroi-sensei has created a small house surrounded by trees, and each individual piece can be removed to become a top.
Hiroi Michiaki: And this is, umm, ah, a miniature garden. This is called making a miniature garden, you create lots of them in boxes. This one is done with tops. This is a house, and there are lots of trees around it, and all of these can be taken off and become tops.