I created a calendar that operates on a button-propelled wheel system. Each press of the button will move the corresponding wheel one day/month. I hid the buttons using a massing of tesselation.

Assembly:

1. Print your parts.
2. glue the button slots to the main casing.
3. Line up the buttons with the correct slot. The patterns should line up.
4. Place the wheels into the casing.
5. Place the top on.
6. Completed!