From "engines" episode # 1183
"A stream of water flowed through the Leda scene.
And in the years just before he painted her,
Leonardo began his studies of moving water. Fluid
flow scholars call Leonardo the first student of
turbulent eddies. His drawings capture that motion
so well his vision must've been stroboscopic. The
water is more than just realistic. It seems alive. And
Leonardo later went from the study of moving water
to the study of blood flow in living beings. "