Here's a little more: https://medium.com/illumination/diving-into-illumination-143396a3f863
Bloody bamboo pens. The nibs were trimmed to reverse italic, because that was the way we did our Devanagari, and had to be held almost vertically. Get the wrong angle, and there'd be no criticism, but no mind-reading was required to get the message.
If all went well, our calligraphy was beautiful. I rarely got more than a character or two before the bamboo ran out of ink and trailed off into lines and scratches.
You really had to concentrate, which was the point - so to speak - of the exercise.