anchor.diff:            i = i + 3
         elseif (tag(1:3).eq.'-xz') then
             xz = 1
  +      elseif (tag(1:5).eq.'-clip') then
  +          i = i + 1
  +          call getarg(i,clip)
         elseif (tag(1:2).eq.'-x') then
             i = i + 1
             call getarg(i,tag)
  
positive.code:       p = 0
        xsec = 0
        xz = 0
        do 100 i = 1,5
            ref(i) = -1.0d0
    100 continue
  
negative.code:                   dz = dd*dtan(ref(5)*d2r)
                    z = ref(3) + dz
                endif
                if (clip.ne.'none') then
                    zsave = z
                    call pnpoly(x,y,xx,yy,nn,io)
                    if (io.eq.-1) z = -12345d0
                endif
                if (p.eq.0.and.xsec.eq.0) then
                    write(101,9999) x,y,z
                elseif (p.eq.1.and.xsec.eq.0) then
  