Interesting. I have aphantasia, visual snow, and at least audio-tactile / sound-color / space-concept synesthesia. I often see a grid of dense, contextually sensitive symbolics overlaid onto backgrounds. For example, I see math-like things on white walls, charts & graphs when I look at gray ones, and kanji-like strokes when I watch anime (I studied Japanese years ago).<p>As a researcher in AGI, it makes me wonder if synesthesia is just a mixture of <i>any</i> senses that happen to develop particularly strong associations rather than a separate pathway. My synesthesia certainly has been getting stronger the more I learn.