diff --git a/active_projects/clacks/all_questions_scenes.py b/active_projects/clacks/all_questions_scenes.py
deleted file mode 100644
index c29d03ce..00000000
--- a/active_projects/clacks/all_questions_scenes.py
+++ /dev/null
@@ -1,8 +0,0 @@
-from active_projects import clacks
-
-output_directory = "clacks_question"
-all_scenes = [
-    clacks.NameIntro,
-    clacks.MathAndPhysicsConspiring,
-    clacks.LightBouncing,
-]
diff --git a/active_projects/clacks/name_bump.py b/active_projects/clacks/name_bump.py
index e7972b53..cd79392d 100644
--- a/active_projects/clacks/name_bump.py
+++ b/active_projects/clacks/name_bump.py
@@ -6,7 +6,7 @@ from active_projects.clacks.question import BlocksAndWallExample
 
 class NameBump(BlocksAndWallExample):
     CONFIG = {
-        "name": "Magnus Lysfjord",
+        "name": "Grant Sanderson",
         "sliding_blocks_config": {
             "block1_config": {
                 "mass": 1e6,
diff --git a/active_projects/clacks/question.py b/active_projects/clacks/question.py
index 17dab588..acefc690 100644
--- a/active_projects/clacks/question.py
+++ b/active_projects/clacks/question.py
@@ -266,6 +266,7 @@ class Wall(Line):
 class BlocksAndWallScene(Scene):
     CONFIG = {
         "include_sound": True,
+        "collision_sound": "clack.wav",
         "count_clacks": True,
         "counter_group_shift_vect": LEFT,
         "sliding_blocks_config": {},
@@ -273,7 +274,6 @@ class BlocksAndWallScene(Scene):
         "wall_x": -6,
         "n_wall_ticks": 15,
         "counter_label": "\\# Collisions: ",
-        "collision_sound": "clack.wav",
         "show_flash_animations": True,
         "min_time_between_sounds": 0.004,
     }
@@ -345,35 +345,30 @@ class BlocksAndWallScene(Scene):
                 return
             self.counter_mob.set_value(n_clacks)
 
-    def create_sound_file(self, clack_data):
-        clack_file = os.path.join(SOUND_DIR, self.collision_sound)
-        output_file = self.get_movie_file_path(extension='.wav')
+    def add_clack_sounds(self, clack_data):
+        clack_file = self.collision_sound
+        total_time = self.get_time()
         times = [
             time
             for location, time in clack_data
-            if time < 300  # In case of any extremes
+            if time < total_time
         ]
-
-        clack = AudioSegment.from_wav(clack_file)
-        total_time = max(times) + 1
-        clacks = AudioSegment.silent(int(1000 * total_time))
-        last_position = 0
-        min_diff = int(1000 * self.min_time_between_sounds)
+        last_time = 0
         for time in times:
-            position = int(1000 * time)
-            d_position = position - last_position
-            if d_position < min_diff:
+            d_time = time - last_time
+            if d_time < self.min_time_between_sounds:
                 continue
-            if time > self.get_time():
-                break
-            last_position = position
-            clacks = clacks.fade(-50, start=position, end=position + 10)
-            clacks = clacks.overlay(
-                clack,
-                position=position
+            last_time = time
+            self.add_sound(
+                clack_file,
+                time_offset=(time - total_time),
+                gain=-20,
             )
-        clacks.export(output_file, format="wav")
-        return output_file
+        return self
+
+    def tear_down(self):
+        if self.include_sound:
+            self.add_clack_sounds(self.clack_data)
 
     # TODO, this no longer works
     # should use Scene.add_sound instead
@@ -1573,6 +1568,7 @@ class Thumbnail(BlocksAndWallExample, MovingCameraScene):
         "count_clacks": False,
         "show_flash_animations": False,
         "floor_y": -3.0,
+        "include_sound": False,
     }
 
     def setup(self):
@@ -1580,7 +1576,16 @@ class Thumbnail(BlocksAndWallExample, MovingCameraScene):
         BlocksAndWallExample.setup(self)
 
     def construct(self):
-        self.camera_frame.shift(0.9 * UP)
+        # self.camera_frame.shift(0.9 * UP)
+        self.mobjects.insert(
+            0,
+            FullScreenFadeRectangle(
+                color=DARK_GREY,
+                opacity=0.5,
+                sheen_direction=UL,
+                sheen=0.5,
+            ),
+        )
         self.thicken_lines()
         self.grow_labels()
         self.add_vector()
diff --git a/active_projects/clacks/solution2.py b/active_projects/clacks/solution2.py
new file mode 100644
index 00000000..0e586de6
--- /dev/null
+++ b/active_projects/clacks/solution2.py
@@ -0,0 +1,15 @@
+# from active_projects.clacks import question
+# from active_projects.clacks import solution1
+from active_projects.clacks.solution2 import block_collision_scenes
+from active_projects.clacks.solution2 import simple_scenes
+
+OUTPUT_DIRECTORY = "clacks_solution2"
+ALL_SCENE_CLASSES = [
+    # question.Thumbnail,
+    # solution1.SolutionThumbnail,
+    # question.BlocksAndWallExampleMass1e2,
+    # question.BlocksAndWallExampleMass1e4,
+    block_collision_scenes.IntroducePreviousTwoVideos,
+    block_collision_scenes.PreviousTwoVideos,
+    simple_scenes.TwoSolutionsWrapper,
+]
diff --git a/active_projects/clacks/solution2/block_collision_scenes.py b/active_projects/clacks/solution2/block_collision_scenes.py
index 3a54fed5..b300087f 100644
--- a/active_projects/clacks/solution2/block_collision_scenes.py
+++ b/active_projects/clacks/solution2/block_collision_scenes.py
@@ -6,58 +6,71 @@ class PreviousTwoVideos(BlocksAndWallExample):
     CONFIG = {
         "sliding_blocks_config": {
             "block1_config": {
-                "mass": 1e4,
-                "velocity": -2,
-                "width": 3,
+                "mass": 1e2,
+                "velocity": -1,
+                "width": 4,
+                "distance": 8,
             },
             "block2_config": {
-                "width": 3,
+                "width": 4,
+                "distance": 3,
             },
         },
+        "floor_y": -3,
         "wait_time": 15,
     }
 
     def setup(self):
-        videos = Group(
-            ImageMobject
-        )
-
-        name_mobs = VGroup(*map(TextMobject, names))
-        name_mobs.set_stroke(BLACK, 3, background=True)
-        name_mobs.set_fill(LIGHT_GREY, 1)
-        name_mobs.set_sheen(3, UL)
-        name_mobs.scale(2)
-        configs = [
-            self.sliding_blocks_config["block1_config"],
-            self.sliding_blocks_config["block2_config"],
-        ]
-        for name_mob, config in zip(name_mobs, configs):
-            config["width"] = name_mob.get_width()
-        self.name_mobs = name_mobs
-
         super().setup()
-
-    def add_blocks(self):
-        super().add_blocks()
         blocks = self.blocks
-        name_mobs = self.name_mobs
+        videos = Group(
+            ImageMobject("ClacksSolution1Thumbnail"),
+            ImageMobject("ClacksQuestionThumbnail"),
+        )
+        for n, video, block in zip([2, 1], videos, blocks):
+            block.fade(1)
+            video.add(SurroundingRectangle(
+                video, buff=0,
+                color=BLUE,
+                stroke_width=3,
+            ))
+            video.replace(block)
 
-        blocks.fade(1)
+            title = TextMobject("Part {}".format(n))
+            title.scale(1.5)
+            title.next_to(video, UP, MED_SMALL_BUFF)
+            video.add(title)
 
-        def update_name_mobs(name_mobs):
-            for name_mob, block in zip(name_mobs, self.blocks):
-                name_mob.move_to(block)
-                target_y = block.get_bottom()[1] + SMALL_BUFF
-                curr_y = name_mob[0].get_bottom()[1]
-                name_mob.shift((target_y - curr_y) * UP)
+        def update_videos(videos):
+            for video, block in zip(videos, blocks):
+                video.move_to(block, DOWN)
+                video.shift(0.04 * UP)
 
-        name_mobs.add_updater(update_name_mobs)
-        self.add(name_mobs)
+        videos.add_updater(update_videos)
+        self.add(videos)
+        if self.show_flash_animations:
+            self.add(self.clack_flashes.mobject)
+        self.videos = videos
 
-        clack_y = self.name_mobs[1].get_center()[1]
-        for location, time in self.clack_data:
-            location[1] = clack_y
 
-        for block, name_mob in zip(blocks, name_mobs):
-            block.label.next_to(name_mob, UP)
-            block.label.set_fill(YELLOW, opacity=1)
+class IntroducePreviousTwoVideos(PreviousTwoVideos):
+    CONFIG = {
+        "show_flash_animations": False,
+        "include_sound": False,
+    }
+
+    def construct(self):
+        blocks = self.blocks
+        videos = self.videos
+
+        self.remove(blocks)
+        videos.clear_updaters()
+        self.remove(videos)
+
+        self.play(FadeInFromLarge(videos[1]))
+        self.play(TransformFromCopy(
+            videos[0].copy().fade(1).shift(2 * RIGHT),
+            videos[0],
+            rate_func=lambda t: rush_into(t, 3),
+        ))
+        # self.wait()
diff --git a/active_projects/clacks/solution2/simple_scenes.py b/active_projects/clacks/solution2/simple_scenes.py
index 955f5503..a4b6ef3b 100644
--- a/active_projects/clacks/solution2/simple_scenes.py
+++ b/active_projects/clacks/solution2/simple_scenes.py
@@ -1,17 +1,48 @@
 from big_ol_pile_of_manim_imports import *
-from active_projects.clacks.question import BlocksAndWallExample
 
 
-class PreviousTwoVideos(BlocksAndWallExample):
+class TwoSolutionsWrapper(Scene):
     CONFIG = {
-        "sliding_blocks_config": {
-            "block1_config": {
-                "mass": 1e0,
-                "velocity": -2,
-            }
-        },
-        "wait_time": 15,
     }
 
     def construct(self):
         pass
+
+
+class ConnectionToOptics(Scene):
+    def construct(self):
+        e_group, m_group = k_groups = self.get_kinematics_groups()
+
+        self.add(k_groups)
+
+    def get_kinematics_groups(self):
+        tex_to_color_map = {
+            "m_1": BLUE,
+            "m_2": BLUE,
+            "v_1": RED,
+            "v_2": RED,
+        }
+        energy_eq = TexMobject(
+            "\\frac{1}{2} m_1 (v_1)^2 + "
+            "\\frac{1}{2} m_2 (v_2)^2 = "
+            "\\text{const.}",
+            tex_to_color_map=tex_to_color_map
+        )
+        momentum_eq = TexMobject(
+            "m_1 v_1 + m_2 v_2 = \\text{const.}",
+            tex_to_color_map=tex_to_color_map
+        )
+        energy_label = TextMobject(
+            "Conservation of energy"
+        )
+        momentum_label = TextMobject(
+            "Conservation of momentum"
+        )
+        energy_group = VGroup(energy_eq, energy_label)
+        momentum_group = VGroup(momentum_eq, momentum_label)
+        groups = VGroup(energy_group, momentum_group)
+        for group in groups:
+            group.arrange_submobjects(DOWN)
+        groups.arrange_submobjects(DOWN, LARGE_BUFF)
+        groups.to_edge(LEFT)
+        return groups
diff --git a/active_projects/clacks_solution2.py b/active_projects/clacks_solution2.py
deleted file mode 100644
index 6840c08d..00000000
--- a/active_projects/clacks_solution2.py
+++ /dev/null
@@ -1,6 +0,0 @@
-from active_projects.clacks.solution2 import block_collision_scenes
-
-OUTPUT_DIRECTORY = "clacks_solution2"
-ALL_SCENE_CLASSES = [
-    block_collision_scenes.PreviousTwoVideos
-]