सरुको हरफ - अंग्रेजी - Launoy and Bienvenu’s toy was a rudimentary...

Launoy and Bienvenu’s toy was a rudimentary helicopter with a central
shaft, corks at both ends with feathers angled to provide lift as they
spun, and a bow (as in bow and arrow) drawn taut by winding its string
around the shaft.