When we talk about exhibition at my school, there is always discussion of the "sizzle" and the "steak". The "sizzle" refers to the look of an exhibition - particularly the transformation of classrooms into unrecognizable, magical-looking spaces - while the "steak" refers to the actual content of the exhibition - the students' demonstrations of their learning.
Sizzle and steak are normally presented as different, even opposing things, but I read the metaphor differently: when you cook a steak, the "sizzle" is the sound of raw material being transformed into something digestible. So "sizzle" strikes me as a defining feature of beautiful work - information shaped by students into something that is meaningful to visitors who attend the exhibition.
What is of more concern to me isn't the "sizzle", it's more like non-edible cake decorations - stuff that looks nice, but doesn't have anything to do with the matter at hand. This year, our mantra for exhibition was "nothing goes on the wall that doesn't help us convey the information we need to convey. This led us to a relatively spartan exhibition, and one that caused consternation among many during the process of setting up the exhibition, but it was an approach that I feel good about.