floored masterpiece
Recent x-ray and other investigation of this well known work has revealed an extraordinary lower layer. While painting, Leonardo's gaze has obviously strayed from his beautiful model to the floor. Without thinking he has painted in a section of the floor, his socks and even part of his jeans.
No doubt an enigmatic cough from the lovely lady brought Leonardo's attention back to the present and he painted over the floor, socks etc with the lovely picture which we all know so well.