Bill Gates bought several of his notebooks at auction for about 28 million I believe
History Channel showed de Vinci's armored "tank", rotating volley gun (a machinegun +), robot on wheels, etc.
His drawing of birds in flight, water moving, horses running - exactly matches stop-frame movies
His eye could capture each "frame" accurately
Yes, he was brilliant.
http://www.visi.com/~reuteler/leonardo.html