Using a refractive filter to show in a single image what is before and behind you is a useful allegory of linear time, and the ability to split light into pretty rainbows can create the illusion that we understand its inner workings, like in the waterfall pictures above and below. There is a danger that the mere effect becomes purpose.
I found another effect more compelling, using a filter patterned with many facets, a little like an insect eye. Below, at the spring, we can see reality repeated and made visible in ghost like images.
What we see are slightly different views of the same scene, shifted against each other, resulting in a mild form of cubism, as in the quarry below.
Much of this can of course done with a single image in Photoshop. Doing it with a movable filter has the advantage that you can play with the constraints of reality while there. You take a picture of what you see, and don’t create what you want to see afterwards.
The effect can be subtle, creating the illusion of a cyclic space in which we can walk freely, refracted as well.