Box 100,10,200,20
Fill 100,10
@V_contour(X%,Y%,F%)
Procedure V_contour(X%,Y%,F%)
  Dpoke Ptsin,X%                    ! coordinates just as the FILL
  Dpoke Ptsin+2,Y%                  ! frame color
  Dpoke Intin,F%
  Dpoke Contrl+2,1
  Dpoke Contrl+6,1
  Vdisys 103
Return