I 'got' zero-based array indexing when I tried making a Tetris clone. If you try to sum Cartesian coordinates stored in an array whose index is 1-based, you hav

I 'got' zero-based array indexing when I tried making a Tetris clone. If you try to sum Cartesian coordinates stored in an array whose index is 1-based, you have to do subtraction to reset the off-by-one error. I can't describe the theory in any more detail than that; I don't even know what I'd have to study to describe the issue using technical vocabulary. But it just clicked for me.