anchor.diff:         phi_i = atan2(y_i, x_i)
          dphi = abs(phi_i - geo%w3(p%icell%i3+1))
          if(dphi > pi) dphi = abs(dphi - twopi)
  -       if(dphi < 0.5 * pi) call insert_t(t2, 6)
  +       if(dphi < 0.5 * pi) call insert_t(t2, 6,e)
   
       end if
   
  
positive.code:        phi_i = atan2(y_i, x_i)
         dphi = abs(phi_i - geo%w3(p%icell%i3))
         if(dphi > pi) dphi = abs(dphi - twopi)
         if(dphi < 0.5 * pi) call insert_t(t1, 5)
  
         ! Find intersection with upper phi wall
         t2 = - ( geo%wtanp(p%icell%i3+1) * p%r%x - p%r%y ) / ( geo%wtanp(p%icell%i3+1) * p%v%x - p%v%y )
  
negative.code:     ! Inner wall
      pC_1 = pC - geo%wr2(p%icell%i1) / v2_xy
      call quadratic_pascal_reduced(pB,pC_1,t1,t2)
      call insert_t(t1,1,e)
      call insert_t(t2,1,e)
  
      ! Outer wall
      pC_2 = pC - geo%wr2(p%icell%i1+1) / v2_xy
      call quadratic_pascal_reduced(pB,pC_2,t1,t2)
      call insert_t(t1,2,e)
      call insert_t(t2,2,e)
  
      ! -------------------------------------------------
      ! z walls
      ! -------------------------------------------------
  
      t1 = ( geo%w2(p%icell%i2)   - p%r%z ) / p%v%z
      call insert_t(t1,3,e)
      t2 = ( geo%w2(p%icell%i2+1) - p%r%z ) / p%v%z
      call insert_t(t2,4,e)
  
      ! -------------------------------------------------
      ! phi walls
  