Ohh, and then we could write the digits in octal.

Interestingly, the N64 internally had 9 bit bytes, just accesses from the CPU ignored one of the bits. This wasn't a parity bit, but instead a true extra data bit that was used by the GPU.

The N64's Reality Display Processor actually used that 9th bit as a coverage mask for antialiasing, allowing per-pixel alpha blending without additional memory lookups.