Interestingly, that was the only one I categorized differently from the authors—I could find a meaning for it. It's not an aphorism in the same way as the others (I'm not clear on whether that was the point, or just whether the statement had to be meaningful in general)—but it could be interpreted as follows:

Something has 'abstract beauty' (as opposed to concrete, surface beauty) through some conceptual significance it contains; however, once you look more, there is a deeper hidden meaning to the concepts, which changes the beauty into something else.

In another interpretation, something can be "superficially" beautiful in an abstract way (say, a fractal or abstract mosaic), but if you can find another meaning in it, it changes the way you see it, probably for the better.

Is that not just a complicated way of saying meaning (intentional or not) is important in art?

"The hidden meaning transforms the abstract beauty."

Not BS! Take for instance, E=mc^2. Thought of as a beautiful equation by many in the sciences. But, one of the hidden meanings is you can make an atomic weapon using it, which transforms it to horror.

It's like #3: You see things differently once you see the pattern.