Rangoli

rangoli.py

def rangoli(size):
    width = size * 4 - 3
    chars = list(string.ascii_lowercase[:size])
    chars.reverse()
    for row in range(1, size + 1):
        chars_left = ''.join(chars[0:row])
        chars_right = ''.join(reversed(chars_left[:-1]))
        print '-'.join(chars_left + chars_right).center(width, '-')
    for row in reversed(range(1, size)):
        chars_left = ''.join(chars[0:row])
        chars_right = ''.join(reversed(chars_left[:-1]))
        print '-'.join(chars_left + chars_right).center(width, '-')