打印菱形
for row_num in range(1, 5):
character = '*'*(2*row_num-1)
print(character.center(13, ' '))
for row_num in [3, 2, 1]:
character = '*'*(2*row_num-1)
print(character.center(13, ' '))
for row_num in range(1, 5):
character = '*'*(2*row_num-1)
print(character.center(13, ' '))
for row_num in [3, 2, 1]:
character = '*'*(2*row_num-1)
print(character.center(13, ' '))