rows = 5
cols = 4

mat = [range(0 + (cols * i), cols + (cols * i), 1) for i in range(rows)]


def print_mat(mat):
    for s in mat:
        print(*s)


def rotate_mat(mat):
    mat = [[mat[row][col] for row in range(rows - 1, -1, -1)] for col in range(cols)]
    return mat


print_mat(mat)
mat = rotate_mat(mat)
print("rotated:")
print_mat(mat)