The second hand runs slightly faster for the first 59 seconds, then freezes for one second and then ticks together with a minute hand.
Looks like this - https://www.youtube.com/watch?v=LJwPOBoy3V8
I was considering getting one, but apparently there are (were?) some production quality issues, so in the end decided against it.
One friend of mine took the class as a senior.
At Caltech then there were two math classes, AMa 95 and Ma 108, that were generally taken in your junior year, and were either prerequisites to or had to be taken simultaneously with nearly every junior and senior class in your major. AMa 95 for engineering and physical science majors, Ma 108 for math majors. These were both a noticeable step up in difficulty compared to the two prior years of math, and if you saw a junior who was tired and in a daze it was probably due to 95 or 108.
My friend took Ma 108.
108 had a way of then haunting you even after you got through it. You'd start noticing that number all over the place. You'd need to go to some office, and it would be room 108. You look at your watch after a leisurely lunch to see if it is time to get back to work, and it is 1:08 pm.
My friend had had enough of that, so when she built her digital clock she made it so it held 1:07 for two minutes and then went straight to 1:09.
The link to such a classic piece of industrial design is very pleasing. Confirmed rumour has it that entrance to a popular design museum in a prominent world city is free to anyone visibly wearing one.
The movement is electronically adjustable to precisely align the second hand and minute hand positions to exactly the right spot.
German railways use the same system as the Swiss ones, so be sure to wear it if you travel to the continent.
In normal operation each clock is stepped forward by a DC pulse each minute, but in the last minute any slow clocks are driven by multiple rapid reverse polarity pulses, which align the hands to the 12:00 o'clock position.
This means that the hands of most clocks smoothly step forward, but any incorrect clocks will catch up by suddenly racing to the 12:00 o'clock position once each hour.
I was envisioning a clock where the second hand dragged the others every time it passed over. So the minute hand would only move when swept over by the minute hand, for as far as it needed to revolve. Similarly, the hour hand.
I would be nice if the minute hand moved the hour hand, but that would be noticeably inaccurate.