In case you are not sure: Of course I mean Leonardo Da Vinci, Leonardo from the village of Vinci, whose Wikipedia entry on his interests takes up a whole line on the screen. His art alone (Mona Lisa, the last supper, the Vitruvian Man) would make him a famous genius, but for him art was just one part of his studies about nature.
Leonardo (15 April 1452 – 2 May 1519) is also credited with making whole lists of inventions and observations about nature that took centuries to be made again, including mechanical devices like tanks or flying machines. Leonardo also made groundbreaking discoveries in optics and engineering additional to.... you get the picture, I guess.
But as far stretched as Leonardo's interest were, so was the order of his notices. His notebooks where only for himself so he painted whatever came to his mind whenever it did. You can find a picture of a flamethrower wedged between a lifelike painting of a bird's feather and a water pump (invented example).
If you want to see that for yourself, you can now look at his notebooks! The British Library has digitized them - 570 loose pages - and you can get a glimpse in the high-res mind of this genius of geniuses:
http://www.bl.uk/manuscripts/Viewer.aspx?ref=arundel_ms_263_f001r
Keep in mind that the manuscript is in (beautifully) handwritten Italian and - we are talking about Leonardo after all - mirrored writing. But the pictures are there!
