def drawLineArrows(vertices, current, SYSSIZE, ax):
    """
    Helper function for Collection.displaySystem()
    Draw Arrows inside the line to show current orientation

    Parameters
    ----------
    vertices : [list]
            A list of position lists of each vertix.
    current : [float]
            The current. Polarity Inverts the orientation.
    SYSSIZE : [type]
            Size of the System for controlling arrow size.
    pyplot : [pyplot]
            The pyplot instance

    """
    lenli = len(vertices)
    for v in range(0, len(vertices) - 1):
        x = vertices[(-(v + 1), v)[current <= 0]]
        y = vertices[(-((v + 2) % lenli), (v + 1) % lenli)[current <= 0]]
        ax.quiver((x[0] + y[0]) / 2, (x[1] + y[1]) / 2, (x[2] + y[2]) / 2, 
            x[0] - y[0], x[1] - y[1], x[2] - y[2], normalize=True, length=
            SYSSIZE / 12, color='k')
        ax.quiver(y[0], y[1], y[2], x[0] - y[0], x[1] - y[1], x[2] - y[2],
            normalize=True, length=SYSSIZE / 12, color='k')
