 "One day I say, if I can find only one hair, only one hair of the eyebrow, I will have definitively the proof that originally Leonardo da Vinci had painted eyelash and eyebrow," said Cotte.The engineer claims that other eyebrow hairs that potentially could have appeared on the painting may have faded or been inadvertently erased by a poor attempt to clean the painting.In addition, Cotte says his work uncovered proof that her hands were originally painted in a slightly different position than in the final portrait.