Apparently, we humans come pre-loaded with synesthesia- babies experience the world as a sort of seamlessly vivid sensory wonderland. Most typical brains undergo a neural pruning process by the age of 9 though, giving our nervous systems a break and allowing us to develop the ability to separate different inputs into discrete sensations. We outgrow it.
Okay, you know that scene when Harry Potter steals a little looksie into the basin in Dumbledore's office (yes, I am a total geek), and we watch as liquid inkblots transform into solid memories? Well it felt just like that. Or like the first time you develop your own film in a darkroom- not knowing how to unspool or expose it, before finally dipping it into a bath that slowly and magically reveals an image. Like that! Except in this case, Roman's thoughts were made concrete to us. And that stinker is far more capable than we imagined, even after our minds were blown by what he did with Soma this summer.