Salvator Mundi shows Jesus Christ giving a blessing with his right hand, and a sphere in his left. It was only recently (2011) rediscovered and authenticated. Before that, the beat up, unrestored, old painting was said to have sold for under $100 in 1958. Leonardo didn’t sign most of his work.
Leonardo da Vinci’s fascination of how light and how it’s reflective qualities work can be seen in the details of the sphere.