Witness the incredible restoration of a very old and rusty perpetual calendar, an essential piece of history brought back to life. The restoration began with a complete disassembly and rust cleaning ...

Just when you think you’ve seen them all, someone comes up with something new and unusual, like the concentric rings of this automated perpetual calendar. What we really like about the design ...

Long before sustainability became a trending topic, people invented reusable, perpetual calendars, but the non-digital versions of these are sometimes complicated tables that are hard to interpret.