The power of 3, 6, and 9

I had read a quote from Nikola Tesla a while go. I think it said "If only you understood the power of 3, 6, and 9, then you would understand the universe." it was something like that. Anyone know what he meant? I think he may be talking about the Pythagoras Theorem, anyone know?

This is the pythagoras theorem. Also the reverse can be applied too, it is called the reverse pythagoras' theorem and is almost the same. Yet this time the hypotenus' length is known, as is the length of one of the other sides, this leaves the third side's length unknown. It follows the same logic as before, the only difference is that here you subtract.