{0, 1}  msd_fib

0 1
0 0 -> 0
1 0 -> 1

1 1
0 0 -> 2
1 0 -> 3
0 1 -> 4
1 1 -> 4

2 0
0 0 -> 0
1 0 -> 1

3 0
0 0 -> 2
1 0 -> 3
0 1 -> 4
1 1 -> 4

4 1
