This is a simple imitation of https://www.instagram.com/p/BosaT7iAJwA/. (This composition uses gradient noise for the line's path, instead of the original's second-order pendulum.)
Each frame, this composition renders the scene many times, moving the camera's location slightly each time, then blends all those images together to produce the output image.
This is one way to simulate camera blur / lens blur / depth of field.
