diff --git a/active_projects/__init__.py b/active_projects/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/active_projects/fourier.py b/active_projects/fourier.py
new file mode 100644
index 00000000..ca667664
--- /dev/null
+++ b/active_projects/fourier.py
@@ -0,0 +1,170 @@
+from helpers import *
+
+
+from animation.animation import Animation
+from animation.transform import *
+from animation.simple_animations import *
+from animation.playground import *
+from animation.continual_animation import *
+from topics.geometry import *
+from topics.characters import *
+from topics.functions import *
+from topics.fractals import *
+from topics.number_line import *
+from topics.combinatorics import *
+from topics.numerals import *
+from topics.three_dimensions import *
+from topics.objects import *
+from topics.probability import *
+from topics.complex_numbers import *
+from scene import Scene
+from scene.reconfigurable_scene import ReconfigurableScene
+from scene.zoomed_scene import *
+from camera import Camera
+from mobject import *
+from mobject.image_mobject import *
+from mobject.vectorized_mobject import *
+from mobject.svg_mobject import *
+from mobject.tex_mobject import *
+from topics.graph_scene import *
+
+class AddingPureFrequencies(PiCreatureScene):
+    def construct(self):
+        self.force_skipping()
+
+        self.add_speaker()
+        self.play_a440()
+        self.measure_air_pressure()
+        self.play_lower_pitch()
+        self.play_mix()
+        self.separate_out_parts()
+        self.add_more_notes()
+
+    def add_speaker(self):
+        speaker = SVGMobject(file_name = "speaker")
+        speaker.to_edge(DOWN)
+
+        self.add(speaker)
+        self.speaker = speaker
+
+    def play_a440(self):
+        randy = self.pi_creature
+        a440_label = TextMobject("A440")
+        a440_label.next_to(self.speaker, UP)
+
+        self.broadcast(
+            FadeIn(a440_label),
+            randy.change, "pondering"
+        )
+        self.dither()
+
+        self.set_variables_as_attrs(a440_label)
+
+    def measure_air_pressure(self):
+        randy = self.pi_creature
+        axes = Axes(
+            y_min = -1, y_max = 3,
+            x_min = 0, x_max = 10,
+            number_line_config = {"include_tip" : False},
+        )
+        axes.stretch_to_fit_height(2)
+        axes.to_corner(UP+LEFT)
+        axes.shift(MED_LARGE_BUFF*DOWN)
+
+        frequency = 1.2
+        func = self.get_wave_func(frequency, axes)
+        graph = axes.get_graph(func)
+        graph.highlight(YELLOW)
+        pressure = TextMobject("Pressure")
+        pressure.next_to(axes.y_axis, UP)
+        pressure.shift_onto_screen()
+        time = TextMobject("Time")
+        time.next_to(axes.x_axis.get_right(), DOWN+LEFT)
+        axes.labels = VGroup(pressure, time)
+        axes.add(axes.labels)
+
+        brace = Brace(Line(
+            axes.coords_to_point(7/frequency, func(7/frequency)),
+            axes.coords_to_point(8/frequency, func(8/frequency)),
+        ), UP)
+        words = brace.get_text("Imagine 440 per second", buff = SMALL_BUFF)
+
+        self.revert_to_original_skipping_status()
+        self.play(
+            FadeIn(pressure),
+            ShowCreation(axes.y_axis)
+        )
+        self.play(
+            Write(time),
+            ShowCreation(axes.x_axis)
+        )
+        self.dither()
+        self.broadcast(
+            ShowCreation(graph, run_time = 4, rate_func = None),
+            randy.change, "erm", graph
+        )
+        self.play(
+            GrowFromCenter(brace),
+            Write(words)
+        )
+        self.dither(2)
+        graph.save_state()
+        self.play(
+            FadeOut(brace),
+            FadeOut(words),
+            graph.fade, 0.7,
+        )
+
+        self.set_variables_as_attrs(
+            axes,
+            A440_func = func,
+            A440_graph = graph,
+        )
+
+    def play_lower_pitch(self):
+        pass
+
+    def play_mix(self):
+        pass
+
+    def separate_out_parts(self):
+        pass
+
+    def add_more_notes(self):
+        pass
+
+
+    ####
+
+    def broadcast(self, *added_anims, **kwargs):
+        kwargs["run_time"] = kwargs.get("run_time", 5)
+        kwargs["n_circles"] = kwargs.get("n_circles", 8)
+        self.play(
+            Broadcast(self.speaker[1], **kwargs),
+            *added_anims
+        )
+
+    def get_wave_func(self, frequency, axes):
+        tail_len = 3.0
+        x_min, x_max = axes.x_min, axes.x_max
+        def func(x):
+            value = 0.8*np.cos(2*np.pi*frequency*x)
+            if x - x_min < tail_len:
+                value *= smooth((x-x_min)/tail_len)
+            if x_max - x < tail_len:
+                value *= smooth((x_max - x )/tail_len)
+            return value + 1.5
+        return func
+
+
+    def create_pi_creature(self):
+        return Randolph().to_corner(DOWN+LEFT)
+
+
+
+
+
+
+
+
+