回复：sorry, not smart enough.

I think it is very hard to explain by letter but number.
I use 4*4: (i,j)=ij =--- (o,p,q,r)=opqr
4000---41,42,43,44 3100---41,42,43,34 3010---41,42,43,24 3001---41,42,43,14
2200---41,42,44,34 2110---41,42,44,24
2101---41,42,44,14 2020---41,42,34,24
2011---41,42,34,14 2002---41,42,24,14
1300---41,43,44,34 1210---41,43,44,24
1201---41,43,44,14 1120---41,43,34,24
1111---41,43,34,31 1102---41,43,24,14
1021---41,44,34,14 1030---41,44,43,42
1012---41,44,24,14
1003---41,34,24,14 0400---42,43,44,34
0310---42,43,44,24 0301---42,43,44,14
0220---42,43,34,24 0211---42,43,34,14
0202---42,43,24,14 0130---42,44,34,24
0121---42,44,34,14 0112---42,44,24,14
0103---42,34,24,14 0040---43,44,34,24
0031---43,44,34,14 0022---43,44,24,14
0013---43,34,24,14 0004---44,34,24,14