@staticmethod
def triangle(width=12):
    """Creates a triangular register inflection.

        ::

            >>> inflection = consort.RegisterInflection.triangle()
            >>> print(format(inflection))
            consort.tools.RegisterInflection(
                inflections=abjad.IntervalSegment(
                    (
                        abjad.NumberedInterval(-6),
                        abjad.NumberedInterval(6),
                        abjad.NumberedInterval(-6),
                        ),
                    item_class=abjad.NumberedInterval,
                    ),
                ratio=abjad.Ratio((1, 1)),
                )

        ::

            >>> inflection = consort.RegisterInflection.triangle(width=6)
            >>> print(format(inflection))
            consort.tools.RegisterInflection(
                inflections=abjad.IntervalSegment(
                    (
                        abjad.NumberedInterval(-3),
                        abjad.NumberedInterval(3),
                        abjad.NumberedInterval(-3),
                        ),
                    item_class=abjad.NumberedInterval,
                    ),
                ratio=abjad.Ratio((1, 1)),
                )

        Emits new register inflection.
        """
    import consort
    half_width = int(width / 2)
    return consort.RegisterInflection(inflections=(-half_width, half_width,
        -half_width), ratio=(1, 1))
