Concave reflectors can be utilised when the source is centred at the focus point. This effect can be used when a parallel beam is needed. The "cat" can testify! Yet, when incurring such an extreme form of Reality- perhaps a unified multiverse, would & could cause a calamity within a paradox & so on, so probably is best left undone : ask Scrodinger's "cat" : this "experiment" has been tried out in "reality" to disastrous effect.
Quantum mechanics state a postulation that if followed correctly, predicates that if the constant (speed of light ) was exceeded, then a whole rift would tear through the fabric of Time- as we know it. So? & Now? Theory exists for the purpose of illumination & the great aRt is in not being blinded (by the science) or hoodwinked by facades of incredible strangeness & quark+charm+glamour hunting. Where wAs I? Oh! Parabolic mirrors! Yes! If you feed the input with the same input, you will get an engagement of the Feedback Syndrome (looping), within which, you will find images that repeat as in say, Fractals'.
In our dreams we can glimpse the "UN-reality " of such environments. I digress but, we must be wary of things that can destroy us. Parallel beams can & should enable Mankind to "beam" matter in one state, to matter in another place or Dimension. But, what if you put in a hat, then sent it to say, our nearest habitable planet? Maybe it may result in relation to the "being" or essence of the Thing: sensors are out- messages are incoming! E.G. if an object is moving in front of you then it will appear to manoeuvre swiftly, while the same object will move more slowly as you navigate away from it- The Parallax Viewpoint. Ergo, said "hat" could terminate its bon voyage as an umbrella; given the phenomenon thus forged. Keep'emPeeled.