It's the most fascinating thing to observe, below is a sketch I drew in wonder yesterday. Until now, I have never seen a rooting and sprouting avocado stone but there is an uncanny resemblance to my drawing Before There Were Saturdays .
My other best friend in London, who it turns out has been making avocado plants this way for years and is currently sprouting lichee stones just by putting them in water, exclaimed with great enthusiasm: "Oh yes! How wonderful, they grow into lovely plants with lovely great big leaves!"