Here is a 200-year calendar in the form of a handy pencil cup. I made it from PVC pipe, with laser-printed "sticker paper", and laser-printed plastic "waterproof paper" for the rotating sleeve. To lock in the setting, the floor of the cup is held, by a wing nut, to the inverted "floor" of a small base cup, which is glued to the sleeve. These floor disks are 3mm acrylic, laser-cut to match the pipe diameter.
Features of the cup:
- Displays any month 1900 - 2099
- Displays month name
- Holds setting even when bumped or handled
- Unambiguous instructions (align year with month)
- Easy to find year: 00-99 in ascending order
- Easy to find month: 12 red months in window
- Rotation limited to valid angles
- It's a useful desktop accessory!