Are ones followed by zeros and vice-versa?
test of irbit1:
       000   001   010   011   100   101   110   111
000    17    15     3    14    14    18    10    15
001    18    14     8    16    14    22    17    10
010    18    15     6    14    14    16    13    15
011    17    13     8    18    21    26    17    13
100    15    16    12    11    18    18    18    18
101    14    10    15    17    18    16    25    15
110    16    12    25    15    23    15    13    22
111    17    15    16    18    16    15    23    14

      kendall tau      std. dev.      probability
       0.011227        0.531589        0.595010

test of irbit2:
       000   001   010   011   100   101   110   111
000    21    12    21    16    17     9    14    15
001    14    17    15    18    10    17    20    16
010    19    17    15    16    17    17     9    14
011    12    18     9    16    13    26    13    13
100    16    18    14    16    12    19    15    11
101    12    21    20    16    17    13     8    15
110    14    18    20    17    12    17    12    19
111    19    16    15    22    19     9    19    13

      kendall tau      std. dev.      probability
      -0.003014       -0.142715        0.886516