Interlocking faces of century, decade, and solar year move against a steady hand.
Disk Clock takes the idea of clock and turns it inside-out by moving the faces instead of the hand. Solar year broadens the horizon to encompass a full year. Disk Century takes it even further, to a span longer than a typical human life. The units of measure are years and decades rather than minutes and hours. To even see the outer disks move takes great patience. And yet, when you do, it becomes possible to truly appreciated the passage of time.