DEFINE 2d MATRIX IN python code example

Example: 2d array pytho

# 2D array that is 3x4 (3 columns, 4 rows)
# note that it is essentially an array of lists
arr = [
		[11, 12, 5],
        [15, 6, 10],
        [10, 8, 12],
        [12, 15, 8]
        ]