This episode explores the critical components driving the humanoid robot revolution, specifically focusing on the debate between rotary and linear actuators. Against the backdrop of a Fast Company article incorrectly stating that many humanoid robots utilize planetary roller screws, the discussion delves into the technical nuances of each actuator type. More significantly, the interviewee highlights that the choice between rotary and linear actuators significantly impacts simulation modeling and reinforcement learning, with rotary actuators offering simpler simulation and potentially faster walking speeds. For instance, the Tesla Bot's early simulation showcased unconnected wrist actuators, illustrating the complexity of linear actuator simulation. In contrast, the prevalence of rotary actuators in fast-walking robots suggests a current industry trend towards this technology. The conversation concludes by emphasizing the importance of understanding this fundamental design choice before investing in specific components, suggesting that the success of a humanoid robot company may hinge more on the efficiency and design of its actuators than on the specific components themselves. This highlights emerging industry patterns reflecting a focus on efficient, robust, and easily simulated actuation systems.