What cognitive patterns are forever out of introspection's reach?

Maybe patterns that are larger (more parallel) than working memory?
⤷ No, bc we can chunk-into-word any regularity that catches our attention.

Which aspects of perception are out of reach of deliberate imagination?

Maybe patterns in raw perception?
⤷ Well, I can look at an object and try-hard imagine it changing colour. With practice, what's the theoretical limit to "visual imposition" like this? How does that even work?