diff --git a/manimlib/__init__.py b/manimlib/__init__.py
index 0a45a9c0..13e41ec0 100644
--- a/manimlib/__init__.py
+++ b/manimlib/__init__.py
@@ -68,4 +68,3 @@ from manimlib.utils.rate_functions import *
 from manimlib.utils.simple_functions import *
 from manimlib.utils.sounds import *
 from manimlib.utils.space_ops import *
-from manimlib.utils.strings import *
diff --git a/manimlib/mobject/coordinate_systems.py b/manimlib/mobject/coordinate_systems.py
index 05d23785..3ad01086 100644
--- a/manimlib/mobject/coordinate_systems.py
+++ b/manimlib/mobject/coordinate_systems.py
@@ -52,10 +52,10 @@ class CoordinateSystem():
     def p2c(self, point):
         """Abbreviation for point_to_coords"""
         return self.point_to_coords(point)
-    
+
     def get_origin(self):
         return self.c2p(*[0] * self.dimension)
-    
+
     @abstractmethod
     def get_axes(self):
         raise Exception("Not implemented")
@@ -336,18 +336,6 @@ class Axes(VGroup, CoordinateSystem):
 
     def get_axes(self):
         return self.axes
-    
-    def get_axis(self, index):
-        return self.get_axes()[index]
-
-    def get_x_axis(self):
-        return self.get_axis(0)
-
-    def get_y_axis(self):
-        return self.get_axis(1)
-
-    def get_z_axis(self):
-        return self.get_axis(2)
 
     def get_all_ranges(self):
         return [self.x_range, self.y_range]
diff --git a/manimlib/mobject/svg/mtex_mobject.py b/manimlib/mobject/svg/mtex_mobject.py
index 31790d9a..b7854dd3 100644
--- a/manimlib/mobject/svg/mtex_mobject.py
+++ b/manimlib/mobject/svg/mtex_mobject.py
@@ -1,5 +1,6 @@
 import itertools as it
 import re
+import sys
 from types import MethodType
 
 from manimlib.mobject.svg.svg_mobject import SVGMobject
@@ -10,19 +11,24 @@ from manimlib.utils.iterables import remove_list_redundancies
 from manimlib.utils.tex_file_writing import tex_to_svg_file
 from manimlib.utils.tex_file_writing import get_tex_config
 from manimlib.utils.tex_file_writing import display_during_execution
+from manimlib.logger import log
 
 
 SCALE_FACTOR_PER_FONT_POINT = 0.001
 
 
-tex_hash_to_mob_map = {}
+TEX_HASH_TO_MOB_MAP = {}
+
+
+def _contains(span_0, span_1):
+    return span_0[0] <= span_1[0] and span_1[1] <= span_0[1]
 
 
 def _get_neighbouring_pairs(iterable):
     return list(adjacent_pairs(iterable))[:-1]
 
 
-class _LabelledTex(SVGMobject):
+class _PlainTex(SVGMobject):
     CONFIG = {
         "height": None,
         "path_string_config": {
@@ -31,11 +37,19 @@ class _LabelledTex(SVGMobject):
         },
     }
 
+
+class _LabelledTex(_PlainTex):
+    def __init__(self, file_name=None, **kwargs):
+        super().__init__(file_name, **kwargs)
+        for glyph in self:
+            glyph.glyph_label = _LabelledTex.color_str_to_label(glyph.fill_color)
+
     @staticmethod
     def color_str_to_label(color_str):
         if len(color_str) == 4:
             # "#RGB" => "#RRGGBB"
             color_str = "#" + "".join([c * 2 for c in color_str[1:]])
+
         return int(color_str[1:], 16) - 1
 
     def get_mobjects_from(self, element, style):
@@ -56,7 +70,7 @@ class _LabelledTex(SVGMobject):
 
 class _TexSpan(object):
     def __init__(self, script_type, label):
-        # script_type: 0 for normal, 1 for subscript, 2 for superscript.
+        # `script_type`: 0 for normal, 1 for subscript, 2 for superscript.
         # Only those spans with `script_type == 0` will be colored.
         self.script_type = script_type
         self.label = label
@@ -70,37 +84,32 @@ class _TexSpan(object):
 
 
 class _TexParser(object):
-    def __init__(self, mtex):
-        self.tex_string = mtex.tex_string
-        strings_to_break_up = remove_list_redundancies([
-            *mtex.isolate, *mtex.tex_to_color_map.keys(), mtex.tex_string
-        ])
-        if "" in strings_to_break_up:
-            strings_to_break_up.remove("")
-        unbreakable_commands = mtex.unbreakable_commands
-
+    def __init__(self, tex_string, additional_substrings):
+        self.tex_string = tex_string
         self.tex_spans_dict = {}
+        self.specified_substrings = []
         self.current_label = 0
-        self.break_up_by_braces()
+        self.brace_index_pairs = self.get_brace_index_pairs()
+        self.add_tex_span((0, len(tex_string)))
+        self.break_up_by_double_braces()
         self.break_up_by_scripts()
-        self.break_up_by_additional_strings(strings_to_break_up)
-        self.merge_unbreakable_commands(unbreakable_commands)
+        self.break_up_by_additional_substrings(additional_substrings)
+        self.check_if_overlap()
         self.analyse_containing_labels()
+        self.specified_substrings = remove_list_redundancies(self.specified_substrings)
 
     @staticmethod
-    def label_to_color_tuple(n):
+    def label_to_color_tuple(rgb):
         # Get a unique color different from black,
         # or the svg file will not include the color information.
-        rgb = n + 1
         rg, b = divmod(rgb, 256)
         r, g = divmod(rg, 256)
         return r, g, b
 
-    @staticmethod
-    def contains(span_0, span_1):
-        return span_0[0] <= span_1[0] and span_1[1] <= span_0[1]
-
     def add_tex_span(self, span_tuple, script_type=0, label=-1):
+        if span_tuple in self.tex_spans_dict:
+            return
+
         if script_type == 0:
             # Should be additionally labelled.
             label = self.current_label
@@ -109,11 +118,14 @@ class _TexParser(object):
         tex_span = _TexSpan(script_type, label)
         self.tex_spans_dict[span_tuple] = tex_span
 
-    def break_up_by_braces(self):
-        tex_string = self.tex_string
-        span_tuples = []
+    def add_specified_substring(self, span_tuple):
+        substring = self.tex_string[slice(*span_tuple)]
+        self.specified_substrings.append(substring)
+
+    def get_brace_index_pairs(self):
+        result = []
         left_brace_indices = []
-        for match_obj in re.finditer(r"(\\*)(\{|\})", tex_string):
+        for match_obj in re.finditer(r"(\\*)(\{|\})", self.tex_string):
             # Braces following even numbers of backslashes are counted.
             if len(match_obj.group(1)) % 2 == 1:
                 continue
@@ -123,17 +135,32 @@ class _TexParser(object):
             else:
                 left_brace_index = left_brace_indices.pop()
                 right_brace_index = match_obj.span(2)[1]
-                span_tuples.append((left_brace_index, right_brace_index))
+                result.append((left_brace_index, right_brace_index))
         if left_brace_indices:
-            self.raise_tex_parsing_error()
+            self.raise_tex_parsing_error("unmatched braces")
+        return result
 
-        self.paired_braces_tuples = span_tuples
-        for span_tuple in span_tuples:
-            self.add_tex_span(span_tuple)
+    def break_up_by_double_braces(self):
+        # Match paired double braces (`{{...}}`).
+        skip_pair = False
+        for prev_span_tuple, span_tuple in _get_neighbouring_pairs(
+            self.brace_index_pairs
+        ):
+            if skip_pair:
+                skip_pair = False
+                continue
+            if all([
+                span_tuple[0] == prev_span_tuple[0] - 1,
+                span_tuple[1] == prev_span_tuple[1] + 1
+            ]):
+                self.add_tex_span(span_tuple)
+                self.add_specified_substring(span_tuple)
+                skip_pair = True
 
     def break_up_by_scripts(self):
+        # Match subscripts & superscripts.
         tex_string = self.tex_string
-        brace_indices_dict = dict(self.tex_spans_dict.keys())
+        brace_indices_dict = dict(self.brace_index_pairs)
         for match_obj in re.finditer(r"((?<!\\)(_|\^)\s*)|(\s+(_|\^)\s*)", tex_string):
             script_type = 1 if "_" in match_obj.group() else 2
             token_begin, token_end = match_obj.span()
@@ -142,11 +169,11 @@ class _TexParser(object):
             else:
                 content_match_obj = re.match(r"\w|\\[a-zA-Z]+", tex_string[token_end:])
                 if not content_match_obj:
-                    self.raise_tex_parsing_error()
+                    self.raise_tex_parsing_error("unclear subscript/superscript")
                 content_span = tuple([
                     index + token_end for index in content_match_obj.span()
                 ])
-                self.add_tex_span(content_span)
+            self.add_tex_span(content_span)
             label = self.tex_spans_dict[content_span].label
             self.add_tex_span(
                 (token_begin, content_span[1]),
@@ -154,11 +181,11 @@ class _TexParser(object):
                 label=label
             )
 
-    def break_up_by_additional_strings(self, strings_to_break_up):
+    def break_up_by_additional_substrings(self, additional_substrings):
         tex_string = self.tex_string
         all_span_tuples = []
-        for string in strings_to_break_up:
-            # Only matches non-crossing strings.
+        for string in additional_substrings:
+            # Only match non-crossing strings.
             for match_obj in re.finditer(re.escape(string), tex_string):
                 all_span_tuples.append(match_obj.span())
 
@@ -175,39 +202,37 @@ class _TexParser(object):
                 if span_begin >= span_end:
                     continue
             span_tuple = (span_begin, span_end)
-            if span_tuple not in self.tex_spans_dict:
-                self.add_tex_span(span_tuple)
+            self.add_tex_span(span_tuple)
+            self.add_specified_substring(span_tuple)
 
-    def merge_unbreakable_commands(self, unbreakable_commands):
-        tex_string = self.tex_string
-        command_merge_spans = []
-        brace_indices_dict = dict(self.paired_braces_tuples)
-        # Braces leading by `unbreakable_commands` shouldn't be marked.
-        for command in unbreakable_commands:
-            for match_obj in re.finditer(re.escape(command), tex_string):
-                merge_begin_index = match_obj.span()[1]
-                merge_end_index = merge_begin_index
-                if merge_end_index not in brace_indices_dict:
+    def check_if_overlap(self):
+        span_tuples = sorted(
+            self.tex_spans_dict.keys(),
+            key=lambda t: (t[0], -t[1])
+        )
+        overlapping_span_pairs = []
+        for i, span_0 in enumerate(span_tuples):
+            for span_1 in span_tuples[i + 1 :]:
+                if span_0[1] <= span_1[0]:
                     continue
-                while merge_end_index in brace_indices_dict:
-                    merge_end_index = brace_indices_dict[merge_end_index]
-                command_merge_spans.append((merge_begin_index, merge_end_index))
-
-        self.tex_spans_dict = {
-            span_tuple: tex_span
-            for span_tuple, tex_span in self.tex_spans_dict.items()
-            if all([
-                not _TexParser.contains(merge_span, span_tuple)
-                for merge_span in command_merge_spans
-            ])
-        }
+                if span_0[1] < span_1[1]:
+                    overlapping_span_pairs.append((span_0, span_1))
+        if overlapping_span_pairs:
+            tex_string = self.tex_string
+            log.error("Overlapping substring pairs occur in MTex:")
+            for span_tuple_pair in overlapping_span_pairs:
+                log.error(", ".join(
+                    f"\"{tex_string[slice(*span_tuple)]}\""
+                    for span_tuple in span_tuple_pair
+                ))
+            sys.exit(2)
 
     def analyse_containing_labels(self):
         for span_0, tex_span_0 in self.tex_spans_dict.items():
             if tex_span_0.script_type != 0:
                 continue
             for span_1, tex_span_1 in self.tex_spans_dict.items():
-                if _TexParser.contains(span_1, span_0):
+                if _contains(span_1, span_0):
                     tex_span_1.containing_labels.append(tex_span_0.label)
 
     def get_labelled_expression(self):
@@ -215,18 +240,18 @@ class _TexParser(object):
         if not self.tex_spans_dict:
             return tex_string
 
+        # Remove the span of extire tex string.
         indices_with_labels = sorted([
             (span_tuple[i], i, span_tuple[1 - i], tex_span.label)
             for span_tuple, tex_span in self.tex_spans_dict.items()
             if tex_span.script_type == 0
             for i in range(2)
-        ], key=lambda t: (t[0], -t[1], -t[2]))
-        # Add one more item to ensure all the substrings are joined.
-        indices_with_labels.append((len(tex_string), 0, 0, 0))
+        ], key=lambda t: (t[0], -t[1], -t[2]))[1:]
 
         result = tex_string[: indices_with_labels[0][0]]
-        index_with_label_pairs = _get_neighbouring_pairs(indices_with_labels)
-        for index_with_label, next_index_with_label in index_with_label_pairs:
+        for index_with_label, next_index_with_label in _get_neighbouring_pairs(
+            indices_with_labels
+        ):
             index, flag, _, label = index_with_label
             next_index, *_ = next_index_with_label
             # Adding one more pair of braces will help maintain the glyghs of tex file...
@@ -244,62 +269,86 @@ class _TexParser(object):
             result += tex_string[index : next_index]
         return result
 
-    def raise_tex_parsing_error(self):
-        raise ValueError(f"Failed to parse tex: \"{self.tex_string}\"")
+    def raise_tex_parsing_error(self, message):
+        raise ValueError(f"Failed to parse tex ({message}): \"{self.tex_string}\"")
 
 
 class MTex(VMobject):
     CONFIG = {
         "fill_opacity": 1.0,
         "stroke_width": 0,
-        "should_center": True,
         "font_size": 48,
-        "height": None,
-        "organize_left_to_right": False,
         "alignment": "\\centering",
         "tex_environment": "align*",
         "isolate": [],
-        "unbreakable_commands": ["\\begin", "\\end"],
         "tex_to_color_map": {},
+        "generate_plain_tex_file": False,
     }
 
     def __init__(self, tex_string, **kwargs):
         super().__init__(**kwargs)
-        self.tex_string = MTex.modify_tex_string(tex_string)
+        tex_string = tex_string.strip()
+        # Prevent from passing an empty string.
+        if not tex_string:
+            tex_string = "\\quad"
+        self.tex_string = tex_string
 
-        tex_parser = _TexParser(self)
-        self.tex_spans_dict = tex_parser.tex_spans_dict
-
-        new_tex = tex_parser.get_labelled_expression()
-        full_tex = self.get_tex_file_body(new_tex)
-        hash_val = hash(full_tex)
-        if hash_val not in tex_hash_to_mob_map:
-            with display_during_execution(f"Writing \"{tex_string}\""):
-                filename = tex_to_svg_file(full_tex)
-                svg_mob = _LabelledTex(filename)
-                tex_hash_to_mob_map[hash_val] = svg_mob
-        self.add(*[
-            submob.copy()
-            for submob in tex_hash_to_mob_map[hash_val]
-        ])
-        self.build_submobjects()
+        self.generate_mobject()
 
         self.init_colors()
         self.set_color_by_tex_to_color_map(self.tex_to_color_map)
+        self.scale(SCALE_FACTOR_PER_FONT_POINT * self.font_size)
 
-        if self.height is None:
-            self.scale(SCALE_FACTOR_PER_FONT_POINT * self.font_size)
-        if self.organize_left_to_right:
-            self.organize_submobjects_left_to_right()
-
-    @staticmethod
-    def modify_tex_string(tex_string):
-        result = tex_string.strip("\n")
-        # Prevent from passing an empty string.
-        if not result:
-            result = "\\quad"
+    def get_additional_substrings_to_break_up(self):
+        result = remove_list_redundancies([
+            *self.tex_to_color_map.keys(), *self.isolate
+        ])
+        if "" in result:
+            result.remove("")
         return result
 
+    def get_parser(self):
+        return _TexParser(self.tex_string, self.get_additional_substrings_to_break_up())
+
+    def generate_mobject(self):
+        tex_string = self.tex_string
+        tex_parser = self.get_parser()
+        self.tex_spans_dict = tex_parser.tex_spans_dict
+        self.specified_substrings = tex_parser.specified_substrings
+
+        plain_full_tex = self.get_tex_file_body(tex_string)
+        plain_hash_val = hash(plain_full_tex)
+        if plain_hash_val in TEX_HASH_TO_MOB_MAP:
+            self.add(*TEX_HASH_TO_MOB_MAP[plain_hash_val].copy())
+            return self
+
+        labelled_expression = tex_parser.get_labelled_expression()
+        full_tex = self.get_tex_file_body(labelled_expression)
+        hash_val = hash(full_tex)
+        if hash_val in TEX_HASH_TO_MOB_MAP and not self.generate_plain_tex_file:
+            self.add(*TEX_HASH_TO_MOB_MAP[hash_val].copy())
+            return self
+
+        with display_during_execution(f"Writing \"{tex_string}\""):
+            filename = tex_to_svg_file(full_tex)
+            svg_mob = _LabelledTex(filename)
+            self.add(*svg_mob.copy())
+            self.build_submobjects()
+        TEX_HASH_TO_MOB_MAP[hash_val] = self
+        if not self.generate_plain_tex_file:
+            return self
+
+        with display_during_execution(f"Writing \"{tex_string}\""):
+            filename = tex_to_svg_file(plain_full_tex)
+            plain_svg_mob = _PlainTex(filename)
+            svg_mob = TEX_HASH_TO_MOB_MAP[hash_val]
+            for plain_submob, submob in zip(plain_svg_mob, svg_mob):
+                plain_submob.glyph_label = submob.glyph_label
+            self.add(*plain_svg_mob.copy())
+            self.build_submobjects()
+        TEX_HASH_TO_MOB_MAP[plain_hash_val] = self
+        return self
+
     def get_tex_file_body(self, new_tex):
         if self.tex_environment:
             new_tex = "\n".join([
@@ -333,7 +382,7 @@ class MTex(VMobject):
                 new_submobjects.append(submobject)
 
         new_glyphs = []
-        current_glyph_label = -1
+        current_glyph_label = 0
         for submob in self.submobjects:
             if submob.glyph_label == current_glyph_label:
                 new_glyphs.append(submob)
@@ -347,45 +396,57 @@ class MTex(VMobject):
     def sort_scripts_in_tex_order(self):
         # LaTeX always puts superscripts before subscripts.
         # This function sorts the submobjects of scripts in the order of tex given.
+        tex_spans_dict = self.tex_spans_dict
         index_and_span_list = sorted([
             (index, span_tuple)
-            for span_tuple, tex_span in self.tex_spans_dict.items()
+            for span_tuple, tex_span in tex_spans_dict.items()
             if tex_span.script_type != 0
             for index in span_tuple
         ])
-        index_and_span_pair = _get_neighbouring_pairs(index_and_span_list)
-        for index_and_span_0, index_and_span_1 in index_and_span_pair:
+
+        switch_range_pairs = []
+        for index_and_span_0, index_and_span_1 in _get_neighbouring_pairs(
+            index_and_span_list
+        ):
             index_0, span_tuple_0 = index_and_span_0
             index_1, span_tuple_1 = index_and_span_1
             if index_0 != index_1:
                 continue
             if not all([
-                self.tex_spans_dict[span_tuple_0].script_type == 1,
-                self.tex_spans_dict[span_tuple_1].script_type == 2
+                tex_spans_dict[span_tuple_0].script_type == 1,
+                tex_spans_dict[span_tuple_1].script_type == 2
             ]):
                 continue
-            submob_slice_0 = self.slice_of_part(
+            submob_range_0 = self.range_of_part(
                 self.get_part_by_span_tuples([span_tuple_0])
             )
-            submob_slice_1 = self.slice_of_part(
+            submob_range_1 = self.range_of_part(
                 self.get_part_by_span_tuples([span_tuple_1])
             )
-            submobs = self.submobjects
-            self.set_submobjects([
-                *submobs[: submob_slice_1.start],
-                *submobs[submob_slice_0],
-                *submobs[submob_slice_1.stop : submob_slice_0.start],
-                *submobs[submob_slice_1],
-                *submobs[submob_slice_0.stop :]
-            ])
+            switch_range_pairs.append((submob_range_0, submob_range_1))
+
+        switch_range_pairs.sort(key=lambda pair: (pair[0].stop, -pair[0].start))
+        indices = list(range(len(self.submobjects)))
+        for submob_range_0, submob_range_1 in switch_range_pairs:
+            indices = [
+                *indices[: submob_range_1.start],
+                *indices[submob_range_0.start : submob_range_0.stop],
+                *indices[submob_range_1.stop : submob_range_0.start],
+                *indices[submob_range_1.start : submob_range_1.stop],
+                *indices[submob_range_0.stop :]
+            ]
+
+        submobs = self.submobjects
+        self.set_submobjects([submobs[i] for i in indices])
 
     def assign_submob_tex_strings(self):
         # Not sure whether this is the best practice...
-        # Just a temporary hack for supporting `TransformMatchingTex`.
+        # This temporarily supports `TransformMatchingTex`.
         tex_string = self.tex_string
+        tex_spans_dict = self.tex_spans_dict
         # Use tex strings including "_", "^".
         label_dict = {}
-        for span_tuple, tex_span in self.tex_spans_dict.items():
+        for span_tuple, tex_span in tex_spans_dict.items():
             if tex_span.script_type != 0:
                 label_dict[tex_span.label] = span_tuple
             else:
@@ -402,7 +463,7 @@ class MTex(VMobject):
             curr_span_tuple = label_dict[curr_label]
             prev_span_tuple = label_dict[prev_label]
             next_span_tuple = label_dict[next_label]
-            containing_labels = self.tex_spans_dict[curr_span_tuple].containing_labels
+            containing_labels = tex_spans_dict[curr_span_tuple].containing_labels
             tex_string_spans.append([
                 prev_span_tuple[1] if prev_label in containing_labels else curr_span_tuple[0],
                 next_span_tuple[0] if next_label in containing_labels else curr_span_tuple[1]
@@ -415,10 +476,11 @@ class MTex(VMobject):
             submob.get_tex = MethodType(lambda inst: inst.tex_string, submob)
 
     def get_part_by_span_tuples(self, span_tuples):
-        labels = remove_list_redundancies(list(it.chain(*[
-            self.tex_spans_dict[span_tuple].containing_labels
+        tex_spans_dict = self.tex_spans_dict
+        labels = set(it.chain(*[
+            tex_spans_dict[span_tuple].containing_labels
             for span_tuple in span_tuples
-        ])))
+        ]))
         return VGroup(*filter(
             lambda submob: submob.submob_label in labels,
             self.submobjects
@@ -464,7 +526,10 @@ class MTex(VMobject):
 
     def set_color_by_tex_to_color_map(self, tex_to_color_map):
         for tex, color in list(tex_to_color_map.items()):
-            self.set_color_by_tex(tex, color)
+            try:
+                self.set_color_by_tex(tex, color)
+            except:
+                pass
         return self
 
     def indices_of_part(self, part):
@@ -480,13 +545,19 @@ class MTex(VMobject):
         part = self.get_part_by_tex(tex, index=index)
         return self.indices_of_part(part)
 
-    def slice_of_part(self, part):
-        indices = self.indices_of_part(part)
-        return slice(indices[0], indices[-1] + 1)
+    def indices_of_all_parts_by_tex(self, tex, index=0):
+        all_parts = self.get_parts_by_tex(tex)
+        return list(it.chain(*[
+            self.indices_of_part(part) for part in all_parts
+        ]))
 
-    def slice_of_part_by_tex(self, tex, index=0):
+    def range_of_part(self, part):
+        indices = self.indices_of_part(part)
+        return range(indices[0], indices[-1] + 1)
+
+    def range_of_part_by_tex(self, tex, index=0):
         part = self.get_part_by_tex(tex, index=index)
-        return self.slice_of_part(part)
+        return self.range_of_part(part)
 
     def index_of_part(self, part):
         return self.indices_of_part(part)[0]
@@ -505,14 +576,11 @@ class MTex(VMobject):
             for span_tuple in self.tex_spans_dict.keys()
         ])
 
-    def print_tex_strings_of_submobjects(self):
-        # For debugging
-        # Work with `index_labels()`
-        print("\n")
-        print(f"Submobjects of \"{self.get_tex()}\":")
+    def list_tex_strings_of_submobjects(self):
+        # Work with `index_labels()`.
+        log.debug(f"Submobjects of \"{self.get_tex()}\":")
         for i, submob in enumerate(self.submobjects):
-            print(f"{i}: \"{submob.get_tex()}\"")
-        print("\n")
+            log.debug(f"{i}: \"{submob.get_tex()}\"")
 
 
 class MTexText(MTex):
diff --git a/manimlib/utils/color.py b/manimlib/utils/color.py
index a3450486..93cc9577 100644
--- a/manimlib/utils/color.py
+++ b/manimlib/utils/color.py
@@ -7,8 +7,6 @@ from manimlib.constants import WHITE
 from manimlib.constants import COLORMAP_3B1B
 from manimlib.utils.bezier import interpolate
 from manimlib.utils.iterables import resize_with_interpolation
-from manimlib.utils.simple_functions import clip_in_place
-from manimlib.utils.space_ops import normalize
 
 
 def color_to_rgb(color):
@@ -105,16 +103,6 @@ def random_color():
     return Color(rgb=(random.random() for i in range(3)))
 
 
-def get_shaded_rgb(rgb, point, unit_normal_vect, light_source):
-    to_sun = normalize(light_source - point)
-    factor = 0.5 * np.dot(unit_normal_vect, to_sun)**3
-    if factor < 0:
-        factor *= 0.5
-    result = rgb + factor
-    clip_in_place(rgb + factor, 0, 1)
-    return result
-
-
 def get_colormap_list(map_name="viridis", n_colors=9):
     """
     Options for map_name:
diff --git a/manimlib/utils/simple_functions.py b/manimlib/utils/simple_functions.py
index e868b6a1..c6a7c5d1 100644
--- a/manimlib/utils/simple_functions.py
+++ b/manimlib/utils/simple_functions.py
@@ -1,14 +1,16 @@
 import inspect
 import numpy as np
 import math
+from functools import lru_cache
 
 
 def sigmoid(x):
     return 1.0 / (1 + np.exp(-x))
 
 
-def choose(n, r):
-    return math.comb(n, r)
+@lru_cache(maxsize=10)
+def choose(n, k):
+    return math.comb(n, k)
 
 
 def gen_choose(n, r):
@@ -37,14 +39,6 @@ def clip(a, min_a, max_a):
     return a
 
 
-def clip_in_place(array, min_val=None, max_val=None):
-    if max_val is not None:
-        array[array > max_val] = max_val
-    if min_val is not None:
-        array[array < min_val] = min_val
-    return array
-
-
 def fdiv(a, b, zero_over_zero_value=None):
     if zero_over_zero_value is not None:
         out = np.full_like(a, zero_over_zero_value)
diff --git a/manimlib/utils/strings.py b/manimlib/utils/strings.py
deleted file mode 100644
index 5e5b5d5c..00000000
--- a/manimlib/utils/strings.py
+++ /dev/null
@@ -1,42 +0,0 @@
-import re
-import string
-
-
-def to_camel_case(name):
-    return "".join([
-        [c for c in part if c not in string.punctuation + string.whitespace].capitalize()
-        for part in name.split("_")
-    ])
-
-
-def initials(name, sep_values=[" ", "_"]):
-    return "".join([
-        (s[0] if s else "")
-        for s in re.split("|".join(sep_values), name)
-    ])
-
-
-def camel_case_initials(name):
-    return [c for c in name if c.isupper()]
-
-
-def complex_string(complex_num):
-    return [c for c in str(complex_num) if c not in "()"]
-
-
-def split_string_to_isolate_substrings(full_string, *isolate):
-    """
-    Given a string, and an arbitrary number of possible substrings,
-    to isolate, this returns a list of strings which would concatenate
-    to make the full string, and in which these special substrings
-    appear as their own elements.
-
-    For example,split_string_to_isolate_substrings("to be or not to be", "to", "be")
-    would return ["to", " ", "be", " or not ", "to", " ", "be"]
-    """
-    pattern = "|".join(*(
-        "({})".format(re.escape(ss))
-        for ss in isolate
-    ))
-    pieces = re.split(pattern, full_string)
-    return list(filter(lambda s: s, pieces))