You are technically correct, but coming up with those magic numbers(43, 48, 63) requires the user to manually try and find them, is more error-prone, and requir

You are technically correct, but coming up with those magic numbers(43, 48, 63) requires the user to manually try and find them, is more error-prone, and requires a whole lot more keypresses for larger blocks that don't fit on one screen. I would argue that the author's way is the more idiomatic usage of vim.