#Matrix Spiral Print
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