There are two dice with empty faces in front of you and a marker. You can mark any number on each of the faces of the two dice, but you have to display all 31 days of the month using the two of them.
Which numbers will you mark on which dice so that you can easily depict all the dates of the month?
How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?