I came across some old code that I wrote when I was about 17:
The BBC Micro came with a built in 6502 assembler (Basic with inline assembly language - awesome!). However it did not have a dis-assembler so I set about writing my own. This was clearly a code review on paper. I remember where I really got stuck was trying to burn this into EEPROM. I kept nearly melting my bedroom carpet trying to erase the EEPROM using my mother's sunlamp. I had to do this frequently because often when I burnt the code into the EEPROM it was incomplete because the voltage regulation on my home built EEPROM burner was not too great.
Blimey! If only I had half the brain cells now that I did then.