Ideas for large blank space on my wall

We have a combined living room and dining room with a large two story back wall. The wall has a really strange window configuration and I’m trying to figure out what to do with that back wall. We painted it and we’re planning to just keep it simple (I have a tendency to overdo it and have been trying to practice restraint). But it still feels like it needs something below those two small square windows. Any ideas or suggestions? We’re going for a modern coastal design through the rest of the house.