Part of Leonardo’s genius lies in the fusion between engineering and art. To have that imagination and combine it with both mechanical understanding and the ability to create meaningful – and beautiful – drawings has inspired engineers for the last half millennium. Some of Leonardo’s inventions were deemed impossible, while many inspired real and recognisable objects that are part of our daily lives, albeit requiring modern materials and technology to make them workable. Here we look at a selection of Leonardo’s drawings and real-life versions created from them. Inspired once more by nature, Leonardo looked to birds and bats when trying to replicate flight. His early design was essentially a glider and, unlike most of his concepts, is one that could well have worked back in the early 16th century. It had a frame made of pine covered with a membrane of silk, and while it would never get off flat ground it could conceivably have worked if launched from a high place. To turn it into a flying, rather than a gliding, machine, Leonardo then added flapping action into his plan, a hand crank providing both vertical and twisting motion to resemble a bird’s movement. The ideas were,...