If you ever get a chance to go to Milan, find your way to Santa Maria delle Grazie - the old monastery/nunnery where da Vinci painted this.
It's faded, but still quite impressive. It's about 30 feet wide and 15 feet tall. When you see it in full size, you'll realize Dan Brown was right about one thing: there is *no way* that the person to the right of Jesus is a dude, though it has always been reported to be St. John the Devine.
A guy who could draw a perfect circle with either hand, who could write in mirrored script, and a whole host of other things, would not have had a "woopsie" and made a dude look like a chick. Zero chance.