$i += $i % 2 ? -1 : 1 # $i ^= 1
      if ( $_ + 1 ) % 12 and not(( $_ + 1 ) % 3)
      or $_ + 1 == 22;
# print $i;
# 170 21 35 4 128 17 62 47 68 8 21 2 0 0 21 98 12 0 8 17 83 11 21 2
# print $i % 16;
# 10 5 3 4 0 1 14 15 4 8 5 2 0 0 5 2 12 0 8 1 3 11 5 2
# J  u s t   a n  o  t h e r   P e r l    h a c k  e r