... or at least, his coordinate system has given me a bright idea for those of us that do teach English to non-native speakers.
In Taiwan I've found one of the most chronic frustrations is (aside from the absolutely baffling inability of nearly all my students to "get" eye contact and being-pointed-at... they simply can't tell if I am looking at them, or all the people around them, and then, if they do see me peering directly into their eyeballs, they don't grasp that it means I want them to respond... but I'm venting!)--is being unable to specify clearly where students should look on the page, or what word they should circle, or where they should write a note, and so forth. No matter how vigorously I point at the page, the best students seem capable of for up to a minute is wobbling their head around and asking their peers where I'm pointing, which of course takes their eyes off where I'm actually pointing.
So it dawned on me this morning: all textbooks should have coordinate axes on the page margins. Letters along the bottom, numbers along the outer edge, or vice versa.