A method for finding the day of the week for any date -- in your head.

Wednesday, September 15, 2021

Calendar Cup

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!