code: def rhombus_polygon(self, X, Y, str_id, hor_size, vert_size):
          
          x0, y0 = X - hor_size, Y   # mid_west
          x1, y1 = X, Y - vert_size  # mid_north
          x2, y2 = X + hor_size, Y   # mid_east
          x3, y3 = X, Y + vert_size  # mid_south
  
          polygon = SvgPolygon(4)
          polygon.set_stroke(width=2, color='black')
          poly_name = gui.SvgText(X, Y + 5, str_id)
          poly_name.attributes['text-anchor'] = 'middle'
          self.sheet.append([polygon, poly_name])
  
          mid_north = [x1, y1]
          mid_south = [x3, y3]
          mid_east = [x2, y2]
          mid_west = [x0, y0]
          
          polygon.add_coord(*mid_north)
          polygon.add_coord(*mid_east)
          polygon.add_coord(*mid_south)
          polygon.add_coord(*mid_west)
  
          return mid_north, mid_south, mid_east, mid_west
docs: Draw a rhombus polygon.
              Horizontal size (-hor_size, +hor_size) and
              vertical size (-vert_size, +vert_size).
              with its center on position X,Y
              and with its str_id as text in the middle.