def METHOD_NAME(self):
    """ Add vdd/gnd rails to the top, (middle), and bottom. """
    self.add_layout_pin_rect_center(text="gnd",
                                    layer=self.route_layer,
                                    offset=vector(0.5 * self.width, 0),
                                    width=self.width)
    # Second gnd of the inverter gate
    if self.vertical:
        self.add_layout_pin_rect_center(text="gnd",
                                        layer=self.route_layer,
                                        offset=vector(0.5 * self.width, self.height),
                                        width=self.width)
    if self.vertical:
        # Shared between two gates
        y_offset = 0.5 * self.height
    else:
        y_offset = self.height
    self.add_layout_pin_rect_center(text="vdd",
                                    layer=self.route_layer,
                                    offset=vector(0.5 * self.width, y_offset),
                                    width=self.width)