"""
Given a 2D array (matrix) named M, print all items of M in a spiral order, clockwise.
For example:

M  =  1   2   3   4   5
       6   7   8   9  10
      11  12  13  14  15
      16  17  18  19  20

The clockwise spiral print is:  1 2 3 4 5 10 15 20 19 18 17 16 11 6 7 8 9 14 13 12

"""
import unittest