The setting is a gym, so it should be set up as such: The floor should be a glossy, rectangular plank wood-like floor with some mats. The floor color should be dark. The walls should be white to contrast with the floor color. The columns should also be white to give continuity to the walls. The ceiling should be white to give continuity to the walls and the beams should also be white. There should also be ceiling air conditioning cassettes and small circular lights on the ceiling for white interior lighting. Add a few opaque silhouettes of people walking around the gym. The goal is to make it look like a contemporary gym.