Here's a design sheet to get the futuristic vocabulary started on the project.
A quick concept for future Shanghai and the final matte painting (above). Both painted over a plate of modern San Francisco.
Here's the tech assembly (above) for a futuristic holographic-billboard. Since the hologram in the film was going to be somewhat transparent, I had to design the structure and projection blades for it.
Below is a bunch of nighttime concepts I designed with Looper's telltale "abandoned" buildings invaded by squatters and the poor. In some buildings you can see campfires lit.