Agreed. They're great Hob.

"And he does them from imaginary angles as well - elevated or aerial plans. Now that must have taken even more effort."

Yes, that has often struck me too. You can't just sit down and draw a view from a much higher elevation - you need to take zillions of measurements on the ground and convert them onto paper. He is often praised for his draughtsmanship but it isn't acknowledged that it is the result of tremendous effort. And all to impart far more information than simply drawing it would have. A true hero.