This is a topic I've thought about for many months, and with increasing restrictions on current Internet usage, it is becoming more relevant. The thought was triggered by a personal project by @JackG and I'd be interested to know how he got on with it. He was attempting to find a new block using a pencil and paper.
It is too long time and that thread was created in 2018 so your memory is very good. Pen and paper mining.
It is far beyond Bitcoin mining lottery like NERDMINER.