Donald Knuth has his secretary print his email. He'll handwrite replies on the paper, and she'll send them out.

I love how the people who basically invented computing prefer doing things using pen and paper, or go really out of their way (emailing screenshots of websites) to avoid certain widespread technologies they helped create.

Long ago some sales dept colleagues did this with large excel spreadsheet. I couldn't stop insulting them in my head (treehugger me fully triggered). Maybe they were all math geniuses ..