They meet in the middle when we talk about layout computation. Layout often flips between needing a globally-optimized solution of some kind(how to pack many bo

They meet in the middle when we talk about layout computation. Layout often flips between needing a globally-optimized solution of some kind(how to pack many boxes given some parameters of box size), and needing a fast, simple dynamic adjustment(same drawing algorithm with different numbers passed in). And what happens is that when the layout gets complex, the simple dynamic adjustment impacts the overall solution. Parts of the layout may also contain their own state, like window positioning. So even in immediate GUI there is retained elements, and vice versa. It's a complex tangle, all in all.