Leonardo da Vinci's Codex Atlanticus - Perpetual Motion Machine - Design 3

Leonardo da Vinci also sketched wheels that had a variety of internal structures with interconnected channels passing through a central axis. He sketched two structures, each with 4 interconnected channels and one structure with 8 interconnected channels. He then developed the structure into four channels, each with three interconnected loops. This design also appears in the Codex Foster II, f. 91r.