One more example of a video-feedback rendering system.
A camera, slowly rotating, is in the center of a cube; the image captured by the camera is pushed through a few different colour transformations, and the results of those are painted onto the walls of the cube in the next frame. Zoomy rainbow trips ensue.
A "Combine image with feedback" node is included in the feedback loop, which blends the new frame with the previous one at a specified opacity. This arrests some intense strobing effects which would otherwise occur, and lends the image a softer, dreamier quality.