Generate random block-code

import random
a = ()
for c in range(10): a += (str(c),)
for c in range(26): a += (chr(c+97),)
d = {}
for c in a: d[random.random()]=c
randmap = list(d.keys())
randmap.sort()
s = ""
for c in randmap: s += d[c]
for c in range(len(s)): s = s[:c*2+1] + ' ' + s[c*2+1:]
s = s[0:11]+'\n'+s[12:23]+'\n'+s[24:35]+'\n'+s[36:47]+'\n'+s[48:59]+'\n'+s[60:71]