0(2,3):  1  [rn,C+]  0  1   (*,*)  (*,*)  1  1
1(5,2):  2  [i2,C-]  1  0   (2,3)  (*,*)  1  2,1,2
2(6,0):  3  [r2,rn]  3  2   (1,*)  (*,*)  3  2,1,2,1
3(6,1):  3  [r2,rn]  2  3   (1,*)  (*,*)  3  2,1,2,1