The Closure Part Closure is what happens when our brains take a few separate parts of a picture and, because they’re lined up just right, interprets them as a single object. If we black out everything except the horse, it’s easy for closure to do its job and give us a single object. Closure with the horse and woman. We also use closure on the trees. In this case we can see some strangeness with occlusion going on, but we still read the broken trees as being a single thing.
The arrow points to the foliage, which is particularly important. The smaller tree in the background passes over the horse’s body. The foliage there lets Magritte keep the relationship between the smaller tree and the larger one ambiguous. It’s one of our clues that we’ve fallen into a space warp.