How did DaVinci sleep 15 mins every 2 hours? What kind of alarm clock did he hav

Question:

How did DaVinci sleep 15 mins every 2 hours? What kind of alarm clock did he have?

I've been researching the sleep method, but I'm not sure how you can do this without a method to wake you up for the first months or so, did DaVinci have a friend shake him up or something?

Best Answer - Chosen by Asker: big glass of water...