I bought this calendar from the MOMA gift shop and brought it home because it is extremely fun to play with. The magnets holding the month marker are perfectly weighted, so one can play with it and the magnet snaps the string into place at each month.  If the build quality were worse, it would not work at all, but because it is very well balanced it is both a visually appealing calendar and fun desk object. This is a case of creative design being executed well.