diff --git a/manimlib/mobject/geometry.py b/manimlib/mobject/geometry.py
index c2e5a037..bdabeb58 100644
--- a/manimlib/mobject/geometry.py
+++ b/manimlib/mobject/geometry.py
@@ -653,7 +653,7 @@ class Vector(Arrow):
 
     def __init__(self, direction=RIGHT, **kwargs):
         if len(direction) == 2:
-            direction = np.append(np.array(direction), 0)
+            direction = np.hstack([direction, 0])
         Arrow.__init__(self, ORIGIN, direction, **kwargs)
 
 
diff --git a/manimlib/mobject/mobject.py b/manimlib/mobject/mobject.py
index 354031a9..c9c04138 100644
--- a/manimlib/mobject/mobject.py
+++ b/manimlib/mobject/mobject.py
@@ -346,10 +346,7 @@ class Mobject(Container):
         This can make transition animations nicer
         """
         def repeat_array(array):
-            return reduce(
-                lambda a1, a2: np.append(a1, a2, axis=0),
-                [array] * count
-            )
+            return np.vstack([array] * count)
         for mob in self.family_members_with_points():
             mob.apply_over_attr_arrays(repeat_array)
         return self
diff --git a/manimlib/mobject/types/point_cloud_mobject.py b/manimlib/mobject/types/point_cloud_mobject.py
index c4edf9fc..121d8239 100644
--- a/manimlib/mobject/types/point_cloud_mobject.py
+++ b/manimlib/mobject/types/point_cloud_mobject.py
@@ -27,7 +27,7 @@ class PMobject(Mobject):
         if not isinstance(points, np.ndarray):
             points = np.array(points)
         num_new_points = len(points)
-        self.points = np.append(self.points, points, axis=0)
+        self.points = np.vstack([self.points, points])
         if rgbas is None:
             color = Color(color) if color else self.color
             rgbas = np.repeat(
@@ -37,7 +37,7 @@ class PMobject(Mobject):
             )
         elif len(rgbas) != len(points):
             raise Exception("points and rgbas must have same shape")
-        self.rgbas = np.append(self.rgbas, rgbas, axis=0)
+        self.rgbas = np.vstack([self.rgbas, rgbas])
         return self
 
     def set_color(self, color=YELLOW_C, family=True):
diff --git a/manimlib/utils/color.py b/manimlib/utils/color.py
index 4053d97a..40c75d55 100644
--- a/manimlib/utils/color.py
+++ b/manimlib/utils/color.py
@@ -58,7 +58,7 @@ def color_to_int_rgb(color):
 
 def color_to_int_rgba(color, opacity=1.0):
     alpha = int(255 * opacity)
-    return np.append(color_to_int_rgb(color), alpha)
+    return np.array([*color_to_int_rgb(color), alpha])
 
 
 def color_gradient(reference_colors, length_of_output):
diff --git a/manimlib/utils/space_ops.py b/manimlib/utils/space_ops.py
index 1c6bbeec..85dc446f 100644
--- a/manimlib/utils/space_ops.py
+++ b/manimlib/utils/space_ops.py
@@ -31,10 +31,10 @@ def quaternion_mult(q1, q2):
 
 
 def quaternion_from_angle_axis(angle, axis):
-    return np.append(
+    return np.hstack([
         np.cos(angle / 2),
         np.sin(angle / 2) * normalize(axis)
-    )
+    ])
 
 
 def angle_axis_from_quaternion(quaternion):
@@ -65,7 +65,7 @@ def rotate_vector(vector, angle, axis=OUT):
         quat_inv = quaternion_conjugate(quat)
         product = reduce(
             quaternion_mult,
-            [quat, np.append(0, vector), quat_inv]
+            [quat, np.hstack([0, vector]), quat_inv]
         )
         return product[1:]
     else: