anchor.diff:  
                  endif                    !! Don't skip this grid
               enddo                       !! i loop
  +            enddo                       !! end of jbc loop
            endif                          !! end idir branch
         enddo                             !! endo mq loop
   
  
positive.code: 
        mth = 5
  
        if (icorner_coarse .eq. 0) then
           ic = 1
           jc = 1
        elseif (icorner_coarse .eq. 1) then
           ic = mx
           jc = 1
        elseif (icorner_coarse .eq. 2) then
           ic = 1
           jc = my
        elseif (icorner_coarse .eq. 3) then
           ic = mx
           jc = my
        endif
  
  c     # Interpolate coarse grid corners to fine grid corner ghost cells
  
negative.code:          if (idir .eq. 0) then
  c           # this ensures that we get 'hanging' corners
  
              do ibc = 1,mbc/2
              if (iface_coarse .eq. 0) then
                 ic = ibc
              elseif (iface_coarse .eq. 1) then
                 ic = mx - ibc + 1
              endif
              do jc = 1,mx
                 i1 = ic
  