#NEWLINE# def plot_interval( self , parameter = 't' ) : #NEWLINE# #INDENT# "The plot interval for the default geometric plot of the Ray. Gives\n        values that will produce a ray that is 10 units long (where a unit is\n        the distance between the two points that define the ray).\n\n        Parameters\n        ==========\n\n        parameter : str, optional\n            Default value is 't'.\n\n        Returns\n        =======\n\n        plot_interval : list\n            [parameter, lower_bound, upper_bound]\n\n        Examples\n        ========\n\n        >>> from sympy import Point, Ray, pi\n        >>> r = Ray((0, 0), angle=pi/4)\n        >>> r.plot_interval()\n        [t, 0, 10]\n\n        " #NEWLINE# t = _symbol ( t ) #NEWLINE# return [ t , 0 , 10 ]