It's like a traditional poem with a cumulative pattern. Here is the key to the house.....in the house burns a light....In the light rests a bed.....and so on. In the beginning, Swanson simply references concrete objects, but as the pattern grows the objects are less literal and more lyrical:
On that bed waits a book.
In that book flies a bird.
In that bird breathes a song...
all about the starry dark.
Read this to your children. They will want to hear it again and again.