Erasing at the blackboard

Reflections on how to design code for a printed book, and general programming lessons to take away from the experience.

A common tic among my old math professors was to compulsively erase or revise what they had written and then immediately chastise themselves for doing so. “I'm sorry, it’s terrible to erase at the blackboard,” they'd mutter immediately after wiping something away.

Teachers who write a lot often erase just to recover space on the board, and it tends to be…