Why is the parabola the most bent, concave, effective mirror? What are some properties of a third order mirror (absolute value of x^3)? There is no uniform focal point. Shouldn't shining a light beam along a normal to the x-axis reflect off of the function multiple times? Then take this to the nth order. Or make it exponential. Does the result of the light beam end up converging to a "focal point" after all of its consecutive reflections? Just some things I am curious about. Thanks!