The following is partial sample output that demonstrates how the game handles
an illegal state.
==========

0 0 0 0 
0 0 0 0 
0 0 0 0 
0 0 0 0 

Enter your next move.
001

1 0 0 0 
0 0 0 0 
0 0 0 0 
0 0 0 0 

Enter your next move.
011

1 1 0 0 
0 0 0 0 
0 0 0 0 
0 0 0 0 
WARNING: Board is not in legal state.

Enter your next move.
023

1 1 3 0 
0 0 0 0 
0 0 0 0 
0 0 0 0 
WARNING: Board is not in legal state.

Enter your next move.
002

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

Enter your next move.