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

def plot_interval(self, parameter='t'):

    t = _symbol(parameter)
    return [t, 0, 10]
