A clock is supposed to tell time. Furthermore, it is supposed to do it accurately and precisely. These days, it is not too difficult to build a mechanical, quartz, digital or atomic clock that is marvelously accurate and precise. But if a clock is not so good, it will have a systematic error, i.e., it will go slightly too fast OR slightly too slow and will, over time, get seriously inaccurate.
On the other hand, a biological clock is messy - it relies on ineractions between molecules. Thus, it will display occasional fluctuations - getting a little bit ahead at one point, a little bit behind at another. But, in the long run, a biological clock is self-correcting and will remain accurate for the entire duration of life of the organism.
This kind of clock - imprecise at short timescales but accurate at long time-scales - is much more difficult for human engineers to design. But someone has just done that!
Now, it appears that the motivation for building such a clock was not to emulate biology, but more of an artistic quirk, a way to do something that grabs the media attention, but it worked. You can see the mechanism of the Escapement here and watch a movie here (for some strange reason, they are hogging the movie for themselves and not providing an embed code).
The designer explains his motivation:
Most clocks just tell time, simply and reliably. Not the $1.8 million "time eater" formally unveiled Friday at Corpus Christi College in Cambridge.
The masterpiece, introduced by famed cosmologist Stephen Hawking, challenges all preconceptions about telling time. It has no hands or digital numbers and it is specially designed to run in erratic fashion, slowing down and speeding up from time to time.
Rather than having it toll the hour by a bell or a cuckoo, the clock relies on the clanking of a chain that falls into a coffin, which then loudly bangs closed.
The clock, four feet in diameter, displays time using light-emitting diodes. The light races around the outer ring once every second, pausing briefly at the actual second; the next ring inside indicates the minute, and the inner ring shows the hour.
The lights are constantly on, the apparent motion regulated mechanically through slots in moving discs.
Weirdly, the clock's pendulum slows down or speeds up. Sometimes it stops, the chronophage shakes a foot and the pendulum moves again.
Because of that, the time display may be as much as a minute off, although it swings back to the correct time every five minutes, said Taylor.