More than half a millennium ago (523 years, to be exact), Leonardo da Vinci designed a parachute.
His design languished unused and largely forgotten (probably because human flight was a few centuries ahead, and no-one thought of jumping out of windows with such things).
Since parachutes became more widespread, there's been interest in finding out whether Leonardo's design would work. There was one problem, however. He used a wooden frame to hold his parachute open. Such things don't fit very well through small aircraft doors - or into parachute packs, for that matter.
In 2000 Adrian Nicholas tried to use a parachute based on Leonardo's design. It didn't work properly, and he had to use a reserve chute (of more modern design) to reach the ground safely.
Last weekend Olivier Vietti-Teppa of Switzerland tried again - and succeeded.
His parachute was made of four equilateral triangles of cloth, seven yards to a side, with no wooden frame and a muslin mosquito-net at the base. He carried a modern reserve parachute, just in case, but didn't need it.
He said after the jump in Payerne, near Geneva: "It worked perfectly. I was unable to steer it, but I just glided gracefully to the ground.
"I came down smack in the middle of the tarmac at Payerne military airport. A perfect jump."
Nicely done, Sir! I hope that somewhere up there, Leonardo's spirit was smiling as you drifted past him.