manim/docs/source/examples.rst

###############
Example Gallery
###############

This gallery contains a collection of best practice code snippets
together with their corresponding video/image output, illustrating
different functionalities all across the library.
These are all under the MIT license, so feel free to copy & paste them to your projects.
Enjoy this taste of Manim!

.. tip::

   This gallery is not the only place in our documentation where you can see explicit
   code and video examples: there are many more in our
   :doc:`reference manual </reference>` -- see, for example, our documentation for
   the modules :mod:`~.tex_mobject`, :mod:`~.geometry`, :mod:`~.moving_camera_scene`,
   and many more.

   Check out our `interactive Jupyter environment <https://mybinder.org/v2/gist/behackl/725d956ec80969226b7bf9b4aef40b78/HEAD?filepath=basic%20example%20scenes.ipynb>`_
   which allows running the examples online, without requiring a local
   installation.

   Also, visit our `Twitter <https://twitter.com/manim_community/>`_ for more
   *manimations*!



Basic Concepts
==============

.. manim:: ManimCELogo
    :save_last_frame:
    :ref_classes: MathTex Circle Square Triangle

    class ManimCELogo(Scene):
        def construct(self):
            self.camera.background_color = "#ece6e2"
            logo_green = "#87c2a5"
            logo_blue = "#525893"
            logo_red = "#e07a5f"
            logo_black = "#343434"
            ds_m = MathTex(r"\mathbb{M}", fill_color=logo_black).scale(7)
            ds_m.shift(2.25 * LEFT + 1.5 * UP)
            circle = Circle(color=logo_green, fill_opacity=1).shift(LEFT)
            square = Square(color=logo_blue, fill_opacity=1).shift(UP)
            triangle = Triangle(color=logo_red, fill_opacity=1).shift(RIGHT)
            logo = VGroup(triangle, square, circle, ds_m)  # order matters
            logo.move_to(ORIGIN)
            self.add(logo)



.. manim:: BraceAnnotation
    :save_last_frame:
    :ref_classes: Brace
    :ref_methods: Brace.get_text Brace.get_tex

    class BraceAnnotation(Scene):
        def construct(self):
            dot = Dot([-2, -1, 0])
            dot2 = Dot([2, 1, 0])
            line = Line(dot.get_center(), dot2.get_center()).set_color(ORANGE)
            b1 = Brace(line)
            b1text = b1.get_text("Horizontal distance")
            b2 = Brace(line, direction=line.copy().rotate(PI / 2).get_unit_vector())
            b2text = b2.get_tex("x-x_1")
            self.add(line, dot, dot2, b1, b2, b1text, b2text)

.. manim:: VectorArrow
    :save_last_frame:
    :ref_classes: Dot Arrow NumberPlane Text

    class VectorArrow(Scene):
        def construct(self):
            dot = Dot(ORIGIN)
            arrow = Arrow(ORIGIN, [2, 2, 0], buff=0)
            numberplane = NumberPlane()
            origin_text = Text('(0, 0)').next_to(dot, DOWN)
            tip_text = Text('(2, 2)').next_to(arrow.get_end(), RIGHT)
            self.add(numberplane, dot, arrow, origin_text, tip_text)

.. manim:: GradientImageFromArray
    :save_last_frame:
    :ref_classes: ImageMobject

    class GradientImageFromArray(Scene):
        def construct(self):
            n = 256
            imageArray = np.uint8(
                [[i * 256 / n for i in range(0, n)] for _ in range(0, n)]
            )
            image = ImageMobject(imageArray).scale(2)
            image.background_rectangle = SurroundingRectangle(image, GREEN)
            self.add(image, image.background_rectangle)


Animations
==========

.. manim:: PointMovingOnShapes
    :ref_classes: Circle Dot Line GrowFromCenter Transform MoveAlongPath Rotating

    class PointMovingOnShapes(Scene):
        def construct(self):
            circle = Circle(radius=1, color=BLUE)
            dot = Dot()
            dot2 = dot.copy().shift(RIGHT)
            self.add(dot)

            line = Line([3, 0, 0], [5, 0, 0])
            self.add(line)

            self.play(GrowFromCenter(circle))
            self.play(Transform(dot, dot2))
            self.play(MoveAlongPath(dot, circle), run_time=2, rate_func=linear)
            self.play(Rotating(dot, about_point=[2, 0, 0]), run_time=1.5)
            self.wait()

.. manim:: MovingAround
    :ref_methods: Mobject.shift VMobject.set_fill Mobject.scale Mobject.rotate

    class MovingAround(Scene):
        def construct(self):
            square = Square(color=BLUE, fill_opacity=1)

            self.play(square.animate.shift(LEFT))
            self.play(square.animate.set_fill(ORANGE))
            self.play(square.animate.scale(0.3))
            self.play(square.animate.rotate(0.4))

.. manim:: MovingAngle
    :ref_classes: Angle
    :ref_methods: Mobject.rotate

    class MovingAngle(Scene):
        def construct(self):
            rotation_center = LEFT

            theta_tracker = ValueTracker(110)
            line1 = Line(LEFT, RIGHT)
            line_moving = Line(LEFT, RIGHT)
            line_ref = line_moving.copy()
            line_moving.rotate(
                theta_tracker.get_value() * DEGREES, about_point=rotation_center
            )
            a = Angle(line1, line_moving, radius=0.5, other_angle=False)
            te = MathTex(r"\theta").move_to(
                Angle(
                    line1, line_moving, radius=0.5 + 3 * SMALL_BUFF, other_angle=False
                ).point_from_proportion(0.5)
            )

            self.add(line1, line_moving, a, te)
            self.wait()

            line_moving.add_updater(
                lambda x: x.become(line_ref.copy()).rotate(
                    theta_tracker.get_value() * DEGREES, about_point=rotation_center
                )
            )

            a.add_updater(
                lambda x: x.become(Angle(line1, line_moving, radius=0.5, other_angle=False))
            )
            te.add_updater(
                lambda x: x.move_to(
                    Angle(
                        line1, line_moving, radius=0.5 + 3 * SMALL_BUFF, other_angle=False
                    ).point_from_proportion(0.5)
                )
            )

            self.play(theta_tracker.animate.set_value(40))
            self.play(theta_tracker.animate.increment_value(140))
            self.play(te.animate.set_color(RED), run_time=0.5)
            self.play(theta_tracker.animate.set_value(350))

.. tip::

   You can use multiple ValueTrackers simultaneously.

.. manim:: MovingDots

    class MovingDots(Scene):
        def construct(self):
            d1,d2=Dot(color=BLUE),Dot(color=GREEN)
            dg=VGroup(d1,d2).arrange(RIGHT,buff=1)
            l1=Line(d1.get_center(),d2.get_center()).set_color(RED)
            x=ValueTracker(0)
            y=ValueTracker(0)
            d1.add_updater(lambda z: z.set_x(x.get_value()))
            d2.add_updater(lambda z: z.set_y(y.get_value()))
            l1.add_updater(lambda z: z.become(Line(d1.get_center(),d2.get_center())))
            self.add(d1,d2,l1)
            self.play(x.animate.set_value(5))
            self.play(y.animate.set_value(4))
            self.wait()

.. manim:: MovingGroupToDestination

    class MovingGroupToDestination(Scene):
        def construct(self):
            group = VGroup(Dot(LEFT), Dot(ORIGIN), Dot(RIGHT, color=RED), Dot(2 * RIGHT)).scale(1.4)
            dest = Dot([4, 3, 0], color=YELLOW)
            self.add(group, dest)
            self.play(group.animate.shift(dest.get_center() - group[2].get_center()))
            self.wait(0.5)

.. manim:: MovingFrameBox
    :ref_modules: manim.mobject.svg.tex_mobject
    :ref_classes: MathTex SurroundingRectangle

    class MovingFrameBox(Scene):
        def construct(self):
            text=MathTex(
                "\\frac{d}{dx}f(x)g(x)=","f(x)\\frac{d}{dx}g(x)","+",
                "g(x)\\frac{d}{dx}f(x)"
            )
            self.play(Write(text))
            framebox1 = SurroundingRectangle(text[1], buff = .1)
            framebox2 = SurroundingRectangle(text[3], buff = .1)
            self.play(
                Create(framebox1),
            )
            self.wait()
            self.play(
                ReplacementTransform(framebox1,framebox2),
            )
            self.wait()

.. manim:: RotationUpdater
    :ref_methods: Mobject.add_updater Mobject.remove_updater

    class RotationUpdater(Scene):
        def construct(self):
            def updater_forth(mobj, dt):
                mobj.rotate_about_origin(dt)
            def updater_back(mobj, dt):
                mobj.rotate_about_origin(-dt)
            line_reference = Line(ORIGIN, LEFT).set_color(WHITE)
            line_moving = Line(ORIGIN, LEFT).set_color(YELLOW)
            line_moving.add_updater(updater_forth)
            self.add(line_reference, line_moving)
            self.wait(2)
            line_moving.remove_updater(updater_forth)
            line_moving.add_updater(updater_back)
            self.wait(2)
            line_moving.remove_updater(updater_back)
            self.wait(0.5)

.. manim:: PointWithTrace
    :ref_classes: Rotating
    :ref_methods: VMobject.set_points_as_corners Mobject.add_updater

    class PointWithTrace(Scene):
        def construct(self):
            path = VMobject()
            dot = Dot()
            path.set_points_as_corners([dot.get_center(), dot.get_center()])
            def update_path(path):
                previous_path = path.copy()
                previous_path.add_points_as_corners([dot.get_center()])
                path.become(previous_path)
            path.add_updater(update_path)
            self.add(path, dot)
            self.play(Rotating(dot, radians=PI, about_point=RIGHT, run_time=2))
            self.wait()
            self.play(dot.animate.shift(UP))
            self.play(dot.animate.shift(LEFT))
            self.wait()


Plotting with Manim
===================

.. manim:: SinAndCosFunctionPlot
    :save_last_frame:
    :ref_modules: manim.scene.graph_scene
    :ref_classes: MathTex
    :ref_methods: GraphScene.setup_axes GraphScene.get_graph GraphScene.get_vertical_line_to_graph GraphScene.input_to_graph_point

    class SinAndCosFunctionPlot(GraphScene):
        def __init__(self, **kwargs):
            GraphScene.__init__(
                self,
                x_min=-10,
                x_max=10.3,
                num_graph_anchor_points=100,
                y_min=-1.5,
                y_max=1.5,
                graph_origin=ORIGIN,
                axes_color=GREEN,
                x_labeled_nums=range(-10, 12, 2),
                **kwargs
            )
            self.function_color = RED

        def construct(self):
            self.setup_axes(animate=False)
            func_graph = self.get_graph(np.cos, self.function_color)
            func_graph2 = self.get_graph(np.sin)
            vert_line = self.get_vertical_line_to_graph(TAU, func_graph, color=YELLOW)
            graph_lab = self.get_graph_label(func_graph, label="\\cos(x)")
            graph_lab2 = self.get_graph_label(func_graph2, label="\\sin(x)",
                                x_val=-10, direction=UP / 2)
            two_pi = MathTex(r"x = 2 \pi")
            label_coord = self.input_to_graph_point(TAU, func_graph)
            two_pi.next_to(label_coord, RIGHT + UP)
            self.add(func_graph, func_graph2, vert_line, graph_lab, graph_lab2, two_pi)

.. manim:: GraphAreaPlot
    :save_last_frame:
    :ref_modules: manim.scenes.graph_scene
    :ref_methods: GraphScene.setup_axes GraphScene.get_graph GraphScene.get_vertical_line_to_graph GraphScene.get_area

    class GraphAreaPlot(GraphScene):
        def __init__(self, **kwargs):
            GraphScene.__init__(
                self,
                x_min=0,
                x_max=5,
                y_min=0,
                y_max=6,
                x_labeled_nums=[0,2,3],
                **kwargs)

        def construct(self):
            self.setup_axes()
            curve1 = self.get_graph(lambda x: 4 * x - x ** 2, x_min=0, x_max=4)
            curve2 = self.get_graph(lambda x: 0.8 * x ** 2 - 3 * x + 4, x_min=0, x_max=4)
            line1 = self.get_vertical_line_to_graph(2, curve1, DashedLine, color=YELLOW)
            line2 = self.get_vertical_line_to_graph(3, curve1, DashedLine, color=YELLOW)
            area1 = self.get_area(curve1, 0.3, 0.6, dx_scaling=10, area_color=BLUE)
            area2 = self.get_area(curve2, 2, 3, bounded=curve1)
            self.add(curve1, curve2, line1, line2, area1, area2)

.. manim:: HeatDiagramPlot
    :save_last_frame:
    :ref_modules: manim.scenes.graph_scene
    :ref_methods: GraphScene.setup_axes GraphScene.coords_to_point

    class HeatDiagramPlot(GraphScene):
        def __init__(self, **kwargs):
            GraphScene.__init__(
                self,
                y_axis_label=r"T[$^\circ C$]",
                x_axis_label=r"$\Delta Q$",
                y_min=-8,
                y_max=30,
                x_min=0,
                x_max=40,
                y_labeled_nums=np.arange(-5, 34, 5),
                x_labeled_nums=np.arange(0, 40, 5),
                **kwargs)

        def construct(self):
            data = [20, 0, 0, -5]
            x = [0, 8, 38, 39]
            self.setup_axes()
            dot_collection = VGroup()
            for time, val in enumerate(data):
                dot = Dot().move_to(self.coords_to_point(x[time], val))
                self.add(dot)
                dot_collection.add(dot)
            l1 = Line(dot_collection[0].get_center(), dot_collection[1].get_center())
            l2 = Line(dot_collection[1].get_center(), dot_collection[2].get_center())
            l3 = Line(dot_collection[2].get_center(), dot_collection[3].get_center())
            self.add(l1, l2, l3)


Special Camera Settings
=======================

.. manim:: FollowingGraphCamera
    :ref_modules: manim.scene.moving_camera_scene
    :ref_classes: GraphScene MovingCameraScene MoveAlongPath Restore
    :ref_methods: Mobject.add_updater

    class FollowingGraphCamera(GraphScene, MovingCameraScene):
        def setup(self):
            GraphScene.setup(self)

        def construct(self):
            self.camera.frame.save_state()
            self.setup_axes(animate=False)
            graph = self.get_graph(lambda x: np.sin(x),
                                   color=BLUE,
                                   x_min=0,
                                   x_max=3 * PI
                                   )
            moving_dot = Dot().move_to(graph.points[0]).set_color(ORANGE)

            dot_at_start_graph = Dot().move_to(graph.points[0])
            dot_at_end_graph = Dot().move_to(graph.points[-1])
            self.add(graph, dot_at_end_graph, dot_at_start_graph, moving_dot)
            self.play(self.camera.frame.animate.scale(0.5).move_to(moving_dot))

            def update_curve(mob):
                mob.move_to(moving_dot.get_center())

            self.camera.frame.add_updater(update_curve)
            self.play(MoveAlongPath(moving_dot, graph, rate_func=linear))
            self.camera.frame.remove_updater(update_curve)

            self.play(Restore(self.camera.frame))

.. manim:: MovingZoomedSceneAround
    :ref_modules: manim.scene.zoomed_scene
    :ref_classes: ZoomedScene BackgroundRectangle UpdateFromFunc
    :ref_methods: Mobject.add_updater ZoomedScene.get_zoomed_display_pop_out_animation

    class MovingZoomedSceneAround(ZoomedScene):
    # contributed by TheoremofBeethoven, www.youtube.com/c/TheoremofBeethoven
        def __init__(self, **kwargs):
            ZoomedScene.__init__(
                self,
                zoom_factor=0.3,
                zoomed_display_height=1,
                zoomed_display_width=6,
                image_frame_stroke_width=20,
                zoomed_camera_config={
                    "default_frame_stroke_width": 3,
                    },
                **kwargs
            )

        def construct(self):
            dot = Dot().shift(UL * 2)
            image = ImageMobject(np.uint8([[0, 100, 30, 200],
                                           [255, 0, 5, 33]]))
            image.height = 7
            frame_text = Text("Frame", color=PURPLE).scale(1.4)
            zoomed_camera_text = Text("Zoomed camera", color=RED).scale(1.4)

            self.add(image, dot)
            zoomed_camera = self.zoomed_camera
            zoomed_display = self.zoomed_display
            frame = zoomed_camera.frame
            zoomed_display_frame = zoomed_display.display_frame

            frame.move_to(dot)
            frame.set_color(PURPLE)
            zoomed_display_frame.set_color(RED)
            zoomed_display.shift(DOWN)

            zd_rect = BackgroundRectangle(zoomed_display, fill_opacity=0, buff=MED_SMALL_BUFF)
            self.add_foreground_mobject(zd_rect)

            unfold_camera = UpdateFromFunc(zd_rect, lambda rect: rect.replace(zoomed_display))

            frame_text.next_to(frame, DOWN)

            self.play(Create(frame), FadeInFrom(frame_text, direction=DOWN))
            self.activate_zooming()

            self.play(self.get_zoomed_display_pop_out_animation(), unfold_camera)
            zoomed_camera_text.next_to(zoomed_display_frame, DOWN)
            self.play(FadeInFrom(zoomed_camera_text, direction=DOWN))
            # Scale in        x   y  z
            scale_factor = [0.5, 1.5, 0]
            self.play(
                frame.animate.scale(scale_factor),
                zoomed_display.animate.scale(scale_factor),
                FadeOut(zoomed_camera_text),
                FadeOut(frame_text)
            )
            self.wait()
            self.play(ScaleInPlace(zoomed_display, 2))
            self.wait()
            self.play(frame.animate.shift(2.5 * DOWN))
            self.wait()
            self.play(self.get_zoomed_display_pop_out_animation(), unfold_camera, rate_func=lambda t: smooth(1 - t))
            self.play(Uncreate(zoomed_display_frame), FadeOut(frame))
            self.wait()

.. manim:: FixedInFrameMObjectTest
    :save_last_frame:
    :ref_classes: ThreeDScene
    :ref_methods: ThreeDScene.set_camera_orientation ThreeDScene.add_fixed_in_frame_mobjects

    class FixedInFrameMObjectTest(ThreeDScene):
        def construct(self):
            axes = ThreeDAxes()
            self.set_camera_orientation(phi=75 * DEGREES, theta=-45 * DEGREES)
            text3d = Text("This is a 3D text")
            self.add_fixed_in_frame_mobjects(text3d)
            text3d.to_corner(UL)
            self.add(axes)
            self.wait()

.. manim:: ThreeDLightSourcePosition
    :save_last_frame:
    :ref_classes: ThreeDScene ThreeDAxes ParametricSurface
    :ref_methods: ThreeDScene.set_camera_orientation

    class ThreeDLightSourcePosition(ThreeDScene):
        def construct(self):
            axes = ThreeDAxes()
            sphere = ParametricSurface(
                lambda u, v: np.array([
                    1.5 * np.cos(u) * np.cos(v),
                    1.5 * np.cos(u) * np.sin(v),
                    1.5 * np.sin(u)
                ]), v_min=0, v_max=TAU, u_min=-PI / 2, u_max=PI / 2,
                checkerboard_colors=[RED_D, RED_E], resolution=(15, 32)
            )
            self.renderer.camera.light_source.move_to(3*IN) # changes the source of the light
            self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES)
            self.add(axes, sphere)


.. manim:: ThreeDCameraRotation
    :ref_classes: ThreeDScene ThreeDAxes
    :ref_methods: ThreeDScene.begin_ambient_camera_rotation ThreeDScene.stop_ambient_camera_rotation

    class ThreeDCameraRotation(ThreeDScene):
        def construct(self):
            axes = ThreeDAxes()
            circle=Circle()
            self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES)
            self.add(circle,axes)
            self.begin_ambient_camera_rotation(rate=0.1)
            self.wait()
            self.stop_ambient_camera_rotation()
            self.move_camera(phi=75 * DEGREES, theta=30 * DEGREES)
            self.wait()

.. manim:: ThreeDCameraIllusionRotation
    :ref_classes: ThreeDScene ThreeDAxes
    :ref_methods: ThreeDScene.begin_3dillusion_camera_rotation ThreeDScene.stop_3dillusion_camera_rotation

    class ThreeDCameraIllusionRotation(ThreeDScene):
        def construct(self):
            axes = ThreeDAxes()
            circle=Circle()
            self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES)
            self.add(circle,axes)
            self.begin_3dillusion_camera_rotation(rate=2)
            self.wait(PI/2)
            self.stop_3dillusion_camera_rotation()

.. manim:: ThreeDSurfacePlot
   :save_last_frame:
   :ref_classes: ThreeDScene ParametricSurface
   
   class ThreeDSurfacePlot(ThreeDScene):
       def construct(self):
           resolution_fa = 42
           self.set_camera_orientation(phi=75 * DEGREES, theta=-30 * DEGREES)

           def param_gauss(u, v):
               x = u
               y = v
               d = np.sqrt(x * x + y * y)
               sigma, mu = 0.4, 0.0
               z = np.exp(-((d - mu) ** 2 / (2.0 * sigma ** 2)))
               return np.array([x, y, z])

           gauss_plane = ParametricSurface(
               param_gauss,
               resolution=(resolution_fa, resolution_fa),
               v_min=-2,
               v_max=+2,
               u_min=-2,
               u_max=+2,
           )

           gauss_plane.scale_about_point(2, ORIGIN)
           gauss_plane.set_style(fill_opacity=1,stroke_color=GREEN)
           gauss_plane.set_fill_by_checkerboard(ORANGE, BLUE, opacity=0.5)
           axes = ThreeDAxes()
           self.add(axes,gauss_plane)


Advanced Projects
=================

.. manim:: OpeningManim
    :ref_classes: Tex MathTex Write FadeInFrom LaggedStart NumberPlane Create
    :ref_methods: NumberPlane.prepare_for_nonlinear_transform

    class OpeningManim(Scene):
        def construct(self):
            title = Tex(r"This is some \LaTeX")
            basel = MathTex(r"\sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}")
            VGroup(title, basel).arrange(DOWN)
            self.play(
                Write(title),
                FadeInFrom(basel, UP),
            )
            self.wait()

            transform_title = Tex("That was a transform")
            transform_title.to_corner(UP + LEFT)
            self.play(
                Transform(title, transform_title),
                LaggedStart(*[FadeOutAndShift(obj, direction=DOWN) for obj in basel]),
            )
            self.wait()

            grid = NumberPlane()
            grid_title = Tex("This is a grid")
            grid_title.scale(1.5)
            grid_title.move_to(transform_title)

            self.add(grid, grid_title)  # Make sure title is on top of grid
            self.play(
                FadeOut(title),
                FadeInFrom(grid_title, direction=DOWN),
                Create(grid, run_time=3, lag_ratio=0.1),
            )
            self.wait()

            grid_transform_title = Tex(
                r"That was a non-linear function \\ applied to the grid"
            )
            grid_transform_title.move_to(grid_title, UL)
            grid.prepare_for_nonlinear_transform()
            self.play(
                grid.animate.apply_function(
                    lambda p: p
                              + np.array(
                        [
                            np.sin(p[1]),
                            np.sin(p[0]),
                            0,
                        ]
                    )
                ),
                run_time=3,
            )
            self.wait()
            self.play(Transform(grid_title, grid_transform_title))
            self.wait()

.. manim:: SineCurveUnitCircle
    :ref_classes: MathTex Circle Dot Line VGroup
    :ref_methods: Mobject.add_updater Mobject.remove_updater
    :ref_functions: always_redraw

    class SineCurveUnitCircle(Scene):
        # contributed by heejin_park, https://infograph.tistory.com/230
        def construct(self):
            self.show_axis()
            self.show_circle()
            self.move_dot_and_draw_curve()
            self.wait()

        def show_axis(self):
            x_start = np.array([-6,0,0])
            x_end = np.array([6,0,0])

            y_start = np.array([-4,-2,0])
            y_end = np.array([-4,2,0])

            x_axis = Line(x_start, x_end)
            y_axis = Line(y_start, y_end)

            self.add(x_axis, y_axis)
            self.add_x_labels()

            self.origin_point = np.array([-4,0,0])
            self.curve_start = np.array([-3,0,0])

        def add_x_labels(self):
            x_labels = [
                MathTex("\pi"), MathTex("2 \pi"),
                MathTex("3 \pi"), MathTex("4 \pi"),
            ]

            for i in range(len(x_labels)):
                x_labels[i].next_to(np.array([-1 + 2*i, 0, 0]), DOWN)
                self.add(x_labels[i])

        def show_circle(self):
            circle = Circle(radius=1)
            circle.move_to(self.origin_point)
            self.add(circle)
            self.circle = circle

        def move_dot_and_draw_curve(self):
            orbit = self.circle
            origin_point = self.origin_point

            dot = Dot(radius=0.08, color=YELLOW)
            dot.move_to(orbit.point_from_proportion(0))
            self.t_offset = 0
            rate = 0.25

            def go_around_circle(mob, dt):
                self.t_offset += (dt * rate)
                # print(self.t_offset)
                mob.move_to(orbit.point_from_proportion(self.t_offset % 1))

            def get_line_to_circle():
                return Line(origin_point, dot.get_center(), color=BLUE)

            def get_line_to_curve():
                x = self.curve_start[0] + self.t_offset * 4
                y = dot.get_center()[1]
                return Line(dot.get_center(), np.array([x,y,0]), color=YELLOW_A, stroke_width=2 )


            self.curve = VGroup()
            self.curve.add(Line(self.curve_start,self.curve_start))
            def get_curve():
                last_line = self.curve[-1]
                x = self.curve_start[0] + self.t_offset * 4
                y = dot.get_center()[1]
                new_line = Line(last_line.get_end(),np.array([x,y,0]), color=YELLOW_D)
                self.curve.add(new_line)

                return self.curve

            dot.add_updater(go_around_circle)

            origin_to_circle_line = always_redraw(get_line_to_circle)
            dot_to_curve_line = always_redraw(get_line_to_curve)
            sine_curve_line = always_redraw(get_curve)

            self.add(dot)
            self.add(orbit, origin_to_circle_line, dot_to_curve_line, sine_curve_line)
            self.wait(8.5)

            dot.remove_updater(go_around_circle)