Thanks for describing your experience.
It’s exactly that, rainbow light… Scientists, mathematicians, 3D enthusiasts and like use “the correct term caustics” because it’s in the dictionary, and because “caustics” is the dictionary term, then it’s has to be the correct one to use. There is no questioning, there is no doubt, there is no emotional connection to the word, and they don’t care. Caustics is caustics no matter if it’s specific usage for describing one of the most beautiful light phenomenon was well thought or not…
And all the rest of the world uses any other sequence of words to describe these magnificent angel rays, play of light and colors, luckily ignorancing “the so to say correct term” yet, I insist, very badly coined for that usage, of caustics ( 
sticks like very on point said @Okidoki ) …
So basically we have one one side where ignorance is bliss in a positive manner, these lucky people ignore that there is a very ugly word scientifically out there describing sucu natural beauty, and these blessed people do care to use their imagination to come up with their own words to at least try to come up to the level of such beauty, like rainbow lights, magical light, fairy lights, angel lights, because one’s creative mind would never think an ugly word serve “as the official correct and best word” to talk about such aesthetic patterns of light. And it’s not even the problem that the word “caustics” is mathematical or scientific in nature that makes it correct, because like I said in another answer, “caustics” is not honoring or connected to any mathematician or scientist who would be hurt, betrayed or affected if the term “caustics” would come, as it should, to be coined differently, as the natural phenomon that the vocable is responsible of expressing and yet rails miserably at such task. I mean “caustics” had only one job, expressing the fantastic science and history and emotions of one specific light phenomenon, and it fails absolutely at that job. And mathematicians, scientists, and 3D professionals just give a damn about the real life emotions a word can cause, but, do they really don’t care, don’t they really never ask themselves, caustics caustics caustics, why the hell caustics is used for that?
And that’s ironic to say the least, because see, like we expressed earlier, the rest of the world, the non academic people, take a lot more care of using beautiful and creative words, knowingly making an effort and consciously looking for emotional connections with the word they use at the very moment of witnessing such admirable lights, showing how much they care about words and emotions… And you know what, the academic people (including all 3D folks, programers, etc…) should care at least twice as much.
You can very easily deduce that many such life experiences with loved ones, friends, students and fellow professionals, is the root of what made me write this post right from the beginning. I saw the sun hit that glass the other day, and “caustics” became so quickly a lame word choice… Anyone can do a very simple social experiment: find a kid around you, a cousin, a niece, idealy them having a limited vocabulary, as not knowing the words prior to the test (nebula and caustics being the word they should not know, obviously if yo have genius kids well… they agree anyway), so the test. Show them pictures of a nebula first, and have them describe it with their own words, as trying to find the official dictionary term, and then do the same with caustics, show them pictures of caustics, and have them use their words. Obviously don’t say the official words, not pior, nor during, and not now. Ok, once that you have showed them the pictures of nebulae and caustics and that they have described what they see and tried to coin a correct wording (yes despite their young age), start telling them the “correct” dictionary words, and above all beware and watch out for their emotions when hearing the words, their emotions, their reaction, the goal is to honestly discern their genuine first emotions when hearing a new word… then you’ll see, how underwhelming "caustics’ is, an anytime emotion and dream killer.
Rainbow lights, magic lights, fairy lights, angels lights, anything else will always be better than “the correct dictionary term”
…i guess
)
…
) likewise with HDRI… some do not understand them and others use them for everthing…
… you need this for that…
-rays