This is the the date and time with the numbers sliding between the top and bottom of the display as they move between the begining and end of each range.
The second moves across once a minute, the minute once an hour, the hour once a day (24 hour time),
the day once a month, and the month once a year.
Each digit of the year moves separately.
The year moves once a decade, the decade once a century, and so on.
Each number moves continuously and changes to the next number right as it passes the moment of change.
Thus the hour reads '23' while it approaches the bottom of the clock and flips to '0' at midnight, jumping back to the top.
The yellow and dark grey circles in the hour track mark the sunrise and sunset (if your location is set correctly).
The moon phase is desplayed in the day-of-month track.
The time is always displayed in the local time according to your computer.
Setting a location far away still shows the sunrise and sunset for that location in your local time zone.
(My computer in Boston may tell me that sunrise in San Francisco is at 9am.)
See also my circular clock.
I was inspired to create this clock by the Long Now 10,000 Year Clock.