There's that old chestnut about how the x86 instruction format -- at least up to the 486 -- is easily hand-assembled in octal [1], and that this may be have been the legacy of a design decision made for the Datapoint 2200. [2]

[1] https://news.ycombinator.com/item?id=30409100 [2] https://en.wikipedia.org/wiki/Datapoint_2200