When Yoichi Masuda set out to design a new legged robot, he found inspiration in the Martian Tripods from the classic sci-fi novel “The War of the Worlds” by H.G. Wells. A three-legged configuration seems to offer some advantages when it comes to walking and balancing, and Masuda became curious about the absence of three-legged animals in nature. Are there evolutionary factors that explain why we haven’t seen any? And if three-legged creatures existed, could there be a universal principle of walking locomotion, common for bipeds, tripeds, and quadrupeds? To explore those questions, Masuda and his colleagues at Osaka University built a three-legged robot named Martian.