In 2012 MIT Professor Amos Winter was asked to develop a lighter, cheaper prosthetic leg for the huge Indian market. And not just a bit cheaper: the new limbs needed to be 90% cheaper than those sold in western markets to meet the needs of the over half a million amputees unable to afford prosthetics that often cost tens of thousands of dollars and lasted only 2-3 years. Under these dramatic constraints, Winter’s team went back to fundamentals and reframed the problem: what could the science of movement teach us about how to design and deliver a radically different prosthetic? Rather than taking a traditional approach, which sought to mimic a human foot, the team focused on a tunable but passive foot design that would instead mimic lower leg movements. By 2019, Winter’s team had unveiled their new, low-cost solution — one that could cheaply and easily be tailored to a patient’s weight and height. It was fundamentally different from existing products in terms of cost, design, and material. This achievement was only possible because the initial constraints imposed on the challenge forced a complete re-thinking of the problem.