How do I create and draw a BowTie polygon on Delphi

so far I did this much. I can compile it but when I run it, I don't see anything


procedure DrawBowTie( const xPaper: TImage ;   // to draw upon
                      const xColor: TColor ) ; // the pen color

// Procedure to draw a BowTie on an Image.
// The BowTie occupies from 1/4 to 3/4 of the Width of the Image,
// and from 1/4 to 3/4 of the Height, with the pinch in the middle
// of the Image.
// Coordinates of the vertexes are calculated from the 1/4 values,
// plus value, Mid, for the pinch area.

var W1Q, H1Q, Mid: integer ;
begin
     W1Q := xPaper.Width div 4 ;  // 1/4 of the Width
     //  2 * W1Q is 2/4 (or 1/2) of the Width
     //  3 * W1Q is 3/4          of the Width

     H1Q := xPaper.Height div 4 ; // 1/4 of the Height
     //  2 * H1Q is 2/4 (or 1/2) of the Height
     //  3 * H1Q is 3/4          of the Height

     Mid := xPaper.Height div 20; // 1/20 of the Height (for Bow "Pinch")

     xPaper.Canvas.Pen.Color := xColor ;  // set drawing color

     xPaper.Canvas.Polygon( [point(  W1Q,  H1Q),      //upper left
                             point(2*W1Q,2*H1Q-Mid),  //upper middle pinch
                             point(3*W1Q,  H1Q),      //upper right
                             point(3*W1Q,3*H1Q),      //lower right
                             point(2*W1Q,2*H1Q+Mid),  //lower middle pinch
                             point(  W1Q,3*H1Q)] )    //lower left

end ;