def construct(self):
    plane = NumberPlane(**self.plane_kwargs)
    plane.main_lines.fade(0.9)
    plane.add(plane.get_axis_labels())
    self.add(plane)
    field = VGroup(*[self.create_vect_field(self.point_charge_start_loc, ((x * RIGHT) + (y * UP))) for x in np.arange((- 9), 9, 1) for y in np.arange((- 5), 5, 1)])
    self.field = field
    self.source_charge = self.Positron().move_to(self.point_charge_start_loc)
    self.source_charge.velocity = np.array((1, 0, 0))
    self.play(FadeIn(self.source_charge))
    self.play(ShowCreation(field))
    self.moving_charge()
def construct(self):
    plane = NumberPlane(**self.plane_kwargs)
    plane.main_lines.fade(0.9)
    plane.add(plane.get_axis_labels())
    self.add(plane)
    field = VGroup(*[self.create_vect_field(self.point_charge_start_loc, ((x * RIGHT) + (y * UP))) for x in np.arange((- 9), 9, 1) for y in np.arange((- 5), 5, 1)])
    self.field = field
    self.source_charge = self.Positron().move_to(self.point_charge_start_loc)
    self.source_charge.velocity = np.array((1, 0, 0))
    self.play(FadeIn(self.source_charge))
    self.play(ShowCreation(field))
    self.moving_charge()