 l s d _ f i b 
 0   0 
 0   - >   1 
 1   0 
 0   - >   2 
 2   0 
 0   - >   3 
 3   0 
 0   - >   4 
 4   0 
 1   - >   5 
 5   0 
 0   - >   6 
 6   0 
 1   - >   7 
 7   1 
 0   - >   7 
