Seeing the [Mendeleev's] table, "getting" it, altered my life. I took to visiting it as often as I could. I copied it into my exercise book and acrried it everywhere; I got to know it so well - visually and conceptually - that I could mentally trace its paths in every direction, going up a group, then turning right on a period, stopping, going down one, yet always knowing where I was. It was like a garden, the garden of numbers I had loved as a child - but unlike this, it was real, a key to the universe. I spent hours now, enchanted, totally absorbed, wandering, making discoveries, n the enchanted garden of Mendeleev.

Uncle Tungsteen, by Oliver Sacks.