We now introduce the concept of dynamical composition, reviewing two types: a composition in time that we term “sequential”; and composition in space that we call “parallel.” We’ll put a bit more focus into that last concept, parallel composition and review what has been done historically, and what can be guaranteed mathematically when the simple templates of week 2 are tasked to worked together “in parallel” on variously more complicated morphologies. The final section of this week’s lesson brings you to the horizons of research into legged mobility. We give examples of how the same composition can be anchored in different bodies, and, conversely, how the same body can be made to run using different compositions. We will conclude with a quick look at the ragged edge of what is known about transitional behaviors such as leaping. Link to bibliography: https://www.coursera.org/learn/robotics-mobility/resources/pqYOc