This is one of the most highly innovative machines designed by Leonardo for the manufacturing of textiles. The machine was designed to perform the stretching, twisting and winding operations simultaneously on three consecutive stretches of thread. The operations were then repeated as the thread regularly fed into the machine. Leonardo's winged spindle, which allowed, first for the stretching, twisting and then for the winding of same section of thread, was the basis for the later development of the continuous spinning machine.
Codex Atlanticus, sheet 1090 v.