ZX81 Typed in Game from the Magazine :- Computer weekly (Squirm)

Guide your worm around the square using the cursor keys,eating the numbers,as you eat you will get longer,try not to bang into the walls,or yourself!

[@davidlamb1107]

I remember trying to do that sort of thing on my Apple //c, and being disappointed when I couldnt get it to work because I really wouldn't have any understanding of what I was doing until years later. Talk about cargo cult programming!