S is obviously the North-South axis, and W is obviously the East-West axis. Now, if e and i are the actual constants, it gets interesting.

Believe it or not, I actually debated whether or not to put parentheses around ng. On the one hand, if I didn't I might get comments or complaints. On the other side, nobody leaves comments any way, so maybe I should do that. On the gripping hand, I'd like to get a third mechanical arm, but that's neither here nor there.