Gray codes in python

gray.py

def gray(n):
    if n == 1:
        return ["0", "1"]
    originals = gray(n - 1)
    prefixedOriginals = ["0" + d for d in originals]
    reflected = list(reversed(originals))
    prefixedReflected = ["1" + d for d in reflected]
    return prefixedOriginals + prefixedReflected


balancedGray8 = """
00 01 03 02 06 0E 0A 0B 09 0D 0F 07 05 04 0C 08
18 1C 14 15 17 1F 3F 37 35 34 3C 38 28 2C 24 25
27 2F 2D 29 39 3D 1D 19 1B 3B 2B 2A 3A 1A 1E 16
36 3E 2E 26 22 32 12 13 33 23 21 31 11 10 30 20
60 70 50 51 71 61 63 73 53 52 72 62 66 6E 7E 76
56 5E 5A 7A 6A 6B EB EA FA DA DE D6 F6 FE EE E6
E2 F2 D2 D3 F3 E3 E1 F1 D1 D0 F0 E0 A0 B0 90 91
B1 A1 A3 B3 93 92 B2 A2 A6 AE BE B6 96 9E 9A BA
AA AB BB 9B 99 9D DD D9 DB FB 7B 5B 59 5D 7D 79
F9 FD BD B9 A9 E9 69 6D 6F 67 65 64 E4 E5 E7 EF
ED AD AF A7 A5 A4 AC EC 6C 68 E8 A8 B8 F8 78 7C
FC BC B4 B5 B7 F7 F5 F4 74 75 77 7F FF BF 9F DF
5F 57 55 54 D4 D5 D7 97 95 94 9C DC 5C 58 D8 98
88 C8 48 4C CC 8C 84 C4 44 45 C5 85 87 C7 47 4F
CF 8F 8D CD 4D 49 C9 89 8B CB 4B 4A CA 8A 8E CE
4E 46 C6 86 82 C2 42 43 C3 83 81 C1 41 40 C0 80
""".split()

# Represent 0's with spaces, and 1's with white blocks.
o = " "
l = "\u2588"

def printGrayCode(grayCode):
    for i in range(8):
        for b in grayCode:
            print(l if b[i] == '1' else o, end='')
        print()

# Get a string like '00011010' from an integer.
toBin = lambda x: "0" * (8 - len(bin(x)) + 2) + bin(x)[2:] 

g8 = [toBin(g) for g in balancedGray8]
printGrayCode(g8)

For a more general balanced Gray code generation method, you might find this useful.