"There is writing which resembles the mosaic of glass you see in stained-glass windows. Such windows are beautiful in themselves and let in the light in colored fragments, but you can't expect to see through them. In the same way, there is poetic writing that is beautiful in itself and can easily affect the emotions, but such writing can be dense and can make for hard reading if you are trying to figure out what's happening.
"Plate glass, on the other hand, has no beauty of its own. Ideally, you ought not to be able to see it at all, but through it you can see all that is happening outside. That is the equivalent of writing that is plain and unadorned. Ideally, in reading such writing, you are not even aware that you are reading. Ideas and events seem merely to flow from the mind of the writer into that of the reader without any barrier between."