diff --git a/active_projects/basel.py b/active_projects/basel.py
index 5d72c415..6af405de 100644
--- a/active_projects/basel.py
+++ b/active_projects/basel.py
@@ -406,7 +406,6 @@ class IntroScene(PiCreatureScene):
 
         self.ellipsis = TexMobject("\cdots")
         self.ellipsis.scale(0.4)
-
         for i in range(5, max_n1):
             
             if i == 5:
@@ -421,7 +420,6 @@ class IntroScene(PiCreatureScene):
                     GrowFromPoint(self.rects[i], self.euler_sum[10].get_center(),
                     run_time = 0.5)
                 )
-
         for i in range(max_n1, max_n2):
             self.play(
                     GrowFromPoint(self.rects[i], self.euler_sum[10].get_center(),
@@ -935,6 +933,7 @@ class MorphIntoSunScene(PiCreatureScene):
             max_opacity_spotlight = SPOTLIGHT_FULL,
 
         )
+        self.wait()
 
         self.light_source.move_source_to(source_point)
 
@@ -960,7 +959,6 @@ class MorphIntoSunScene(PiCreatureScene):
             fill_opacity = 1.0,
             stroke_width = 0.0
         )
-
         self.screen.next_to(morty,LEFT)
 
         self.light_source.set_screen(self.screen)
diff --git a/topics/geometry.py b/topics/geometry.py
index 64b3bce1..d2e9363f 100644
--- a/topics/geometry.py
+++ b/topics/geometry.py
@@ -96,6 +96,57 @@ class Arc(VMobject):
         
         return self
 
+
+
+class ArcBetweenPoints(Arc):
+
+    def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
+        if angle == 0:
+            raise Exception("Arc with zero curve angle: use Line instead.")
+
+        midpoint = 0.5 * (start_point + end_point)
+        distance_vector = end_point - start_point
+        normal_vector = np.array([-distance_vector[1], distance_vector[0],0])
+        distance = np.linalg.norm(normal_vector)
+        normal_vector /= distance
+        if angle < 0:
+            normal_vector *= -1
+
+        radius = distance/2 / np.sin(0.5 * np.abs(angle))
+        l = distance/2 / np.tan(0.5 * np.abs(angle))
+        arc_center = midpoint + l * normal_vector
+        w = start_point - arc_center
+        if w[0] != 0:
+            start_angle = np.arctan2(w[1],w[0])
+        else:
+            start_angle = np.pi/2
+
+        Arc.__init__(self, angle,
+            radius = radius,
+            start_angle = start_angle,
+            **kwargs)
+        
+        self.move_arc_center_to(arc_center)
+
+class CurvedArrow(ArcBetweenPoints):
+
+    def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
+        # I know this is in reverse, but it works
+        if angle >= 0:
+            ArcBetweenPoints.__init__(self, start_point, end_point, angle = angle, **kwargs)
+            self.add_tip(at_start = True, at_end = False)
+        else:
+            ArcBetweenPoints.__init__(self, end_point, start_point, angle = -angle, **kwargs)
+            self.add_tip(at_start = False, at_end = True)
+        
+
+class CurvedDoubleArrow(ArcBetweenPoints):
+
+    def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
+        ArcBetweenPoints.__init__(self, start_point, end_point, angle = angle, **kwargs)
+        self.add_tip(at_start = True, at_end = True)
+
+
 class Circle(Arc):
     CONFIG = {
         "color" : RED,
diff --git a/topics/light.py b/topics/light.py
index 4d19ba27..84ca07d2 100644
--- a/topics/light.py
+++ b/topics/light.py
@@ -29,10 +29,10 @@ NUM_LEVELS = 30
 NUM_CONES = 7 # in first lighthouse scene
 NUM_VISIBLE_CONES = 5 # ibidem
 ARC_TIP_LENGTH = 0.2
-AMBIENT_FULL = 0.5
-AMBIENT_DIMMED = 0.2
-SPOTLIGHT_FULL = 0.9
-SPOTLIGHT_DIMMED = 0.2
+AMBIENT_FULL = 0.8
+AMBIENT_DIMMED = 0.5
+SPOTLIGHT_FULL = 0.8
+SPOTLIGHT_DIMMED = 0.5
 LIGHTHOUSE_HEIGHT = 0.8
 
 DEGREES = TAU/360
@@ -57,7 +57,7 @@ class LightSource(VMobject):
         "source_point": VectorizedPoint(location = ORIGIN, stroke_width = 0, fill_opacity = 0),
         "color": LIGHT_COLOR,
         "num_levels": 10,
-        "radius": 5,
+        "radius": 10.0,
         "screen": None,
         "opacity_function": inverse_quadratic(1,2,1),
         "max_opacity_ambient": AMBIENT_FULL,
@@ -142,7 +142,9 @@ class LightSource(VMobject):
                 num_levels = self.num_levels,
                 radius = self.radius,
                 screen = new_screen,
-                camera_mob = self.camera_mob
+                camera_mob = self.camera_mob,
+                opacity_function = self.opacity_function,
+                max_opacity = self.max_opacity_spotlight,
             )
             self.spotlight.move_source_to(self.get_source_point())
 
@@ -423,7 +425,7 @@ class Spotlight(VMobject):
         "color" : GREEN, # LIGHT_COLOR,
         "max_opacity" : 1.0,
         "num_levels" : 10,
-        "radius" : 5.0,
+        "radius" : 10.0,
         "screen" : None,
         "camera_mob": None
     }
diff --git a/topics/number_line.py b/topics/number_line.py
index 9d02286c..3848feba 100644
--- a/topics/number_line.py
+++ b/topics/number_line.py
@@ -120,6 +120,9 @@ class NumberLine(VMobject):
             result.add(mob)
         return result
 
+    def get_labels(self):
+        return self.get_number_mobjects()
+
     def add_numbers(self, *numbers, **kwargs):
         self.numbers = self.get_number_mobjects(
             *numbers, **kwargs
@@ -219,29 +222,7 @@ class Axes(VGroup):
         return graph
 
     def input_to_graph_point(self, x, graph):
-        if hasattr(graph, "underlying_function"):
-            return self.coords_to_point(x, graph.underlying_function(x))
-        else:
-            #binary search
-            lh, rh = 0, 1
-            while abs(lh - rh) > 0.001:
-                mh = np.mean([lh, rh])
-                hands = [lh, mh, rh]
-                points = map(graph.point_from_proportion, hands)
-                lx, mx, rx = map(self.x_axis.point_to_number, points)
-                if lx <= x and rx >= x:
-                    if mx > x:
-                        rh = mh
-                    else:
-                        lh = mh
-                elif lx <= x and rx <= x:
-                    return points[2]
-                elif lx >= x and rx >= x:
-                    return points[0]
-                elif lx > x and rx < x:
-                    lh, rh = rh, lh
-            return points[1]
-
+        return self.coords_to_point(x, graph.underlying_function(x))
 
 class ThreeDAxes(Axes):
     CONFIG = {