 l s d _ 2   l s d _ 2 
 0   0 
 0   0   - >   0 
 0   1   - >   1 
 1   1   - >   2 
 1   0 
 0   0   - >   1 
 0   1   - >   3 
 2   1 
 0   0   - >   2 
 3   0 
 0   0   - >   1 
 1   0   - >   2 
 0   1   - >   3 
