I first came across an advert for the Geochron clock about 10 years ago. It was on a flight to Mexico and there on the inside of the in-flight magazine was an advert for this astonishing piece of horological engineering. The Geochron is essentially a large mechanical map of the world that tracks in real time. It not only displays the time of day across all the timezones, it also charts a number of astronomical phenomena including the position of the moon, the sun's declination, analemma, sunrise and sunset.

For a number of years all I had was the magazine clipping until one day I walked into a new bookshop in Greenwich and there on the wall was a Geochron. Up close it really is a remarkable instrument. Every time I visited the shop I studied the movement and the mechanism.

I don't intend to make an online version of the Geochron but it does have a number of ingenious implementation ideas that I think could work just as well in the digital world. The perpetually looping map could work when reviewing days on a timeline.