We present RayGraphy display technology that renders volumetric graphics by superimposing the trajectories of lights in indoor space filled with fog. Since the traditional FogScreen approach requires the shaping of a thin layer of fog, it can only show two-dimensional images in a narrow range that is close to the fog-emitting nozzle. Although a method that renders volumetric graphics with plasma generated using high-power laser was also proposed, its operation in a public space is considered quite dangerous. The proposed system mainly comprises dozens of laser projectors circularly arranged in a fog-filled space, and renders volumetric graphics in a fog by superimposing weak laser beams from the projectors. Compared to the conventional methods, this system employing weak laser beams and the non-shaped innocuous fog is more scalable and safer. We aim to construct a new spatial augmented reality platform where computer-generated images can be drawn directly in the real world. We implement a prototype that consists of 32 laser projectors and a fog machine. Moreover, we evaluate and discuss the system performance and characteristics in experiments.