The problem with doubling the speed of the small hand is that it would subtly imply that unix time will wrap around to 0, Jan 1st 1970, which is a common misconception and of course not true - it wraps to somewhere in 1901.
I've considered annotating the left side of the dial with the negative numbers also, e.g. ff (-01), etc., which would make it clearer that there's a discontinuity at 80, but it's also a lot of visual mess and on balance I prefer the cleaner look.
I hope that anyone wondering "why 0x80" will be curious enough to go read the linked wikipedia article, which goes into much more detail.
I've considered annotating the left side of the dial with the negative numbers also, e.g. ff (-01), etc., which would make it clearer that there's a discontinuity at 80, but it's also a lot of visual mess and on balance I prefer the cleaner look.
I hope that anyone wondering "why 0x80" will be curious enough to go read the linked wikipedia article, which goes into much more detail.