>>> outside
[[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]
>>> for i in range(0, 16):
...     outside[i / 4][i % 4] = cipher[i]
...
>>> outside
[['r', 'n', 'n', 'd'], ['r', 'n', 'n', 'd'], ['r', 'n', 'n', 'd'], ['r', 'n', 'n', 'd']]
>>> cipher
'aauancvlrerurnndltmeaeepbytusticeatnpmeyiicgogorchsrsocnntiiimihaoofpagsivttpsitlbolrotoex'