Yeah, there's not much 4-bit-ness that's an aid to understanding what it is today. One is that NUL, space, and '0' all have the low 4 bits zero because they're

Yeah, there's not much 4-bit-ness that's an aid to understanding what it is today. One is that NUL, space, and '0' all have the low 4 bits zero because they're all in some sense ‘nothing’.