4 tier cascading waterfall with koi fish in the bottom bowl. Posts, Bowls, and Koi are in separate files because it may potentially be cheaper to use pvc as a post but some may want to print. In any case a small indent is there to attach the post or pvc pipe. The base is hollow to hide wires etc for the small water pump needed to make this work. Each Koi has a small hole in the bottom to be glued to the posts in the base bowl.