Repository: ManimCommunity/manim
File: manim/mobject/geometry.py (Python)

Code before:
                # a shorter arrow has a shorter tip and smaller stroke width
                arrow_5 = Arrow(start=ORIGIN, end=config.top).shift(LEFT * 4)
                arrow_6 = Arrow(start=config.top + DOWN, end=config.top).shift(LEFT * 3)
                g3 = Group(arrow_5, arrow_6)

                self.add(Group(g1, g2, g3).arrange(buff=2))


    .. manim:: ArrowExample
        :save_last_frame:

        class ArrowExample(Scene):
            def construct(self):
                # LEFT Column: Varying Buff
                v1 = VGroup()
                # As buff increases, the size of the arrow decreases.
                # The max buff is (1/2)*(Length of Arrow).
                # In this case, the arrow is 4 units long.
                for i in np.arange(0, 2.2, 0.45):
                    v1 += Arrow(buff=i, start=2 * LEFT, end=2 * RIGHT)
                # Required to arrange arrows.
                v1.arrange_in_grid(cols=1)
                v1.move_to(4 * LEFT)

                # MIDDLE Column: Varying max_stroke_width_to_length_ratio
                v2 = VGroup()
                # As max_stroke_width_to_length_ratio gets bigger,
                # the width of stroke increases.
                for i in np.arange(0, 5, 0.5):
                    v2 += Arrow(max_stroke_width_to_length_ratio=i)
                v2.arrange_in_grid(cols=1)

                # UPPER RIGHT Column: Varying max_tip_length_to_length_ratio
                v3 = VGroup()
                # As max_tip_length_to_length_ratio increases,
                # the length of the tip increases.
                for i in np.arange(0, 0.3, 0.1):
                    v3 += Arrow(max_tip_length_to_length_ratio=i)
                v3.arrange_in_grid(cols=1)
                v3.move_to(4 * RIGHT + 2 * UP)

                # LOWER RIGHT Column: Different types of ArrowTip and colors.
                v4 = VGroup()
                v4 += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareTip)
                v4 += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareFilledTip)
                v4 += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleTip)
                v4 += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleFilledTip)
                v4.arrange_in_grid(cols=1)
                v4.move_to(4 * RIGHT + 2 * DOWN)

                self.add(v1, v2, v3, v4)

Review comment (suggestion):
Same as the previous comment.
```suggestion
                middle_group = VGroup()
```

Code after:
                # a shorter arrow has a shorter tip and smaller stroke width
                arrow_5 = Arrow(start=ORIGIN, end=config.top).shift(LEFT * 4)
                arrow_6 = Arrow(start=config.top + DOWN, end=config.top).shift(LEFT * 3)
                g3 = Group(arrow_5, arrow_6)

                self.add(Group(g1, g2, g3).arrange(buff=2))


    .. manim:: ArrowExample
        :save_last_frame:

        class ArrowExample(Scene):
            def construct(self):
                left_group = VGroup()
                # As buff increases, the size of the arrow decreases.
                for buff in np.arange(0, 2.2, 0.45):
                    left_group += Arrow(buff=buff, start=2 * LEFT, end=2 * RIGHT)
                # Required to arrange arrows.
                left_group.arrange(DOWN)
                left_group.move_to(4 * LEFT)

                middle_group = VGroup()
                # As max_stroke_width_to_length_ratio gets bigger,
                # the width of stroke increases.
                for i in np.arange(0, 5, 0.5):
                    middle_group += Arrow(max_stroke_width_to_length_ratio=i)
                middle_group.arrange(DOWN)

                UR_group = VGroup()
                # As max_tip_length_to_length_ratio increases,
                # the length of the tip increases.
                for i in np.arange(0, 0.3, 0.1):
                    UR_group += Arrow(max_tip_length_to_length_ratio=i)
                UR_group.arrange(DOWN)
                UR_group.move_to(4 * RIGHT + 2 * UP)

                DR_group = VGroup()
                DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareTip)
                DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareFilledTip)
                DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleTip)
                DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleFilledTip)
                DR_group.arrange(DOWN)
                DR_group.move_to(4 * RIGHT + 2 * DOWN)

                self.add(left_group, middle_group, UR_group, DR_group)


    See Also
    --------
    :class:`ArrowTip`
    :class:`CurvedArrow`