When I was a kid before we had legos we had some soviet alternative called constructor or something. Everything was made from metal, crews etc. obviously as a kid one of the first “hello world” things you will build is “plug” that you can insert into those holes in the wall. My older brother was lucky when he did it as the fuse in the house went off. My younger brother did the same about a decade later but holding in his hand two metal pins. He was also lucky that my dad was just passing through corridor and pushed him out. He got away with just burned skin on the fingers and a bit of shock.