This number is 12. That is exactly the number of months in a year and the sides (faces) of a dodecahedron. This is the most suitable polyhedron so that all 12 months of the year can be placed on its faces.
Therefore, on the eve of the upcoming New Year, we offer you to make not just a polyhedron but a whole twelve-sided calendar.
The procedure is simple: download the shape net dodecahedron - calendar, print on thick paper, cut, and glue.
Calendar for 2018 on your table!