4           4            A real, A imag, B real, B imag
     1     2     3     4
     2     2     3     4
     3     3     3     4
     4     4     4     4
     4           4
     4     4     4     4
     4     3     3     3
     4     3     2     2
     4     3     2     1
     4           4
     1     0     0     0
     0     1     0     0
     0     0     1     0
     0     0     0     1
     4           4
     0     0     0     0
     0     0     0     0
     0     0     0     0
     0     0     0     0