4 4 16

0	1	2	3
0	1	2	3
0	1	2	3
0	1	2	3

 0 	13 	 3 	14
12 	 1 	15 	 2
 7 	10 	 4 	 9
11 	 6 	 8 	 5


This is generated by the 1/2 AWGN code (5 7) operated twice, ie,
(xk+1 xki) [xk-1 xk-2] -> [xk+1 xki].

intermediate states:

00 21 02 23
00 21 02 23
10 31 12 33
10 31 12 33

output:

00 31 03 32
30 01 33 02
13 22 10 21
23 12 20 11

and in decimal:

 0 13  3 14
12  1 15  2
 7 10  4  9
11  6  8  5