I saw a lovely Waldorf calendar, and decided to go ahead and replicate it as well as I could.
The calendar itself is plastic canvas covered in grey/brown wool yarn, with parallel cuts in the trunk to provide “windows” for the day, date, and month. And write all the numbers, days, and months, on their sticks. To change the date, simply slide from one day to another.
I also sewed a “pocket” which is green on one side and red on the other, with flowers stitched on the inside of the green side.
Flowers for spring, green for summer, red for fall. And bare branches for winter.
Very simple, and useable from year to year.