From 571efd4669b08d0893949557dd38e6c84beb29bd Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grantsanderson7@gmail.com>
Date: Fri, 7 Jul 2017 23:23:09 -0700
Subject: [PATCH] All animation for 256 bit video

---
 256.py                         | 106 ++++++++++++++++++++++++++++++++-
 animation/simple_animations.py |   5 ++
 2 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/256.py b/256.py
index 9ef5a16c..05aa3bfc 100644
--- a/256.py
+++ b/256.py
@@ -42,6 +42,19 @@ def get_google_logo():
     result.gradient_highlight(*colors)
     return result
 
+class LastVideo(Scene):
+    def construct(self):
+        title = TextMobject("Crypto", "currencies", arg_separator = "")
+        title[0].highlight(YELLOW)
+        title.scale(1.5)
+        title.to_edge(UP)
+        screen_rect = ScreenRectangle(height = 6)
+        screen_rect.next_to(title, DOWN)
+
+        self.add(title)
+        self.play(ShowCreation(screen_rect))
+        self.dither()
+
 class BreakUp2To256(PiCreatureScene):
     def construct(self):
         self.initialize_bits()
@@ -657,6 +670,14 @@ class MainBreakdown(Scene):
             height = 1,
         )
         
+class WriteTWoTo160(Scene):
+    def construct(self):
+        mob = TextMobject("$2^{160}$ ", "Hashes/sec")
+        mob[0].highlight(BLUE)
+        mob.scale(2)
+        self.play(Write(mob))
+        self.dither()
+
 class StateOfBitcoin(TeacherStudentsScene):
     def construct(self):
         title = TextMobject("Total", "B", "mining")
@@ -765,7 +786,90 @@ class StateOfBitcoin(TeacherStudentsScene):
         ))
         self.dither()
 
-
+class QAndA(PiCreatureScene):
+    def construct(self):
+        self.pi_creature.center().to_edge(DOWN)
+        self.show_powers_of_two()
+
+        num_subscriber_words = TexMobject(
+            "> 2^{18} = 262{,}144", "\\text{ subscribers}"
+        )
+        num_subscriber_words.to_edge(UP)
+        num_subscriber_words.shift(RIGHT)
+        num_subscriber_words.highlight_by_tex("subscribers", RED)
+
+        q_and_a = TextMobject("Q\\&A")
+        q_and_a.next_to(self.pi_creature.get_corner(UP+LEFT), UP)
+        q_and_a.save_state()
+        q_and_a.shift(DOWN)
+        q_and_a.set_fill(opacity = 0)
+
+        reddit = TextMobject("reddit.com/r/3blue1brown")
+        reddit.next_to(num_subscriber_words, DOWN, LARGE_BUFF)
+        twitter = TextMobject("@3blue1brown")
+        twitter.highlight(BLUE_C)
+        twitter.next_to(reddit, DOWN)
+
+        self.play(Write(num_subscriber_words))
+        self.play(self.pi_creature.change, "gracious", num_subscriber_words)
+        self.dither()
+        self.play(
+            q_and_a.restore,
+            self.pi_creature.change, "raise_right_hand",
+        )
+        self.dither()
+        self.play(Write(reddit))
+        self.dither()
+        self.play(
+            FadeIn(twitter),
+            self.pi_creature.change_mode, "shruggie"
+        )
+        self.dither(2)
+
+    def show_powers_of_two(self):
+        rows = 16
+        cols = 64
+        dots = VGroup(*[
+            VGroup(*[
+                Dot() for x in range(rows)
+            ]).arrange_submobjects(DOWN, buff = SMALL_BUFF)
+            for y in range(cols)
+        ]).arrange_submobjects(RIGHT, buff = SMALL_BUFF)
+        dots.scale_to_fit_width(2*SPACE_WIDTH - 2*LARGE_BUFF)
+        dots.next_to(self.pi_creature, UP)
+        dots = VGroup(*it.chain(*dots))
+        top = dots.get_top()
+        dots.sort_submobjects(
+            lambda p : np.linalg.norm(p-top)
+        )
+
+        powers_of_two = VGroup(*[
+            Integer(2**i)
+            for i in range(int(np.log2(rows*cols))+1)
+        ])
+
+        curr_power = powers_of_two[0]
+        curr_power.to_edge(UP)
+        self.play(
+            Write(curr_power),
+            FadeIn(dots[0])
+        )
+        for i, power_of_two in enumerate(powers_of_two):
+            if i == 0:
+                continue
+            power_of_two.to_edge(UP)
+            self.play(
+                FadeIn(VGroup(*dots[2**(i-1) : 2**i])),
+                Transform(
+                    curr_power, power_of_two,
+                    rate_func = squish_rate_func(smooth, 0, 0.5)
+                )
+            )
+        self.dither()
+        self.play(
+            FadeOut(dots),
+            FadeOut(powers_of_two)
+        )
 
 
 
diff --git a/animation/simple_animations.py b/animation/simple_animations.py
index 13d8874b..d3c1a45f 100644
--- a/animation/simple_animations.py
+++ b/animation/simple_animations.py
@@ -141,6 +141,11 @@ class ShowPassingFlash(ShowPartial):
         upper = min(1, alpha + self.time_width/2)
         return (lower, upper)
 
+    def clean_up(self, *args, **kwargs):
+        ShowPartial.clean_up(self, *args, **kwargs)
+        for submob, start_submob in self.get_all_families_zipped():
+            submob.pointwise_become_partial(start_submob, 0, 1)
+
 class MoveAlongPath(Animation):
     def __init__(self, mobject, vmobject, **kwargs):
         digest_config(self, kwargs, locals())