1984, Jet Set Willy was released. A great game that every kid at school wanted. Of course we all wanted a copy, but it cost £8 here in the UK, which was several weeks' pocket money.
Copying games then involved finding a kid whose Dad was seriously into Hifi and had a stackable stereo system, then we'd copy it with their tape to tape system. But JSW had this as the cassette inlay.
How this works? When the game loaded after about 10-15 minutes, it would ask what colours were in Grid square A5, or H9 etc. Get it wrong twice and the game would exit and you'd need to start over.
(If you're wondering what happens if you're colour blind - you could write to the publishers and if they accepted your complaint, they would ask you to send them the game and would give you a cheque to cover the refund)
Of course, kids are determined and inventive, and this was well before photocopiers or digital cameras, so we would spend our lunchtimes with pencil and paper writing down every single combination...
It was a good game, with some great music, but really really hard.
(Credit to https://intarch.ac.uk/journal/issue45/2/1.html for the picture, and the page also goes into more depth)
All of these oold copy protections were so annoying. Some would just give you a page number from the manual and ask for the fifth word. Some AD&D games came with a decoder wheel with elvish runes n shit (looking at your Pool of Radiance!). At least the decoder wheel was fun to throw around at your friends.