Work-in-progress: new surface for mining tunnels, produced mathematically on-the-fly so that the pattern is extremely varied and volumetric, based on 3D coordinates so it looks more like actual rock veins, although right now this isn't also the case for surface normal mapping.
The top image shows how the color pattern extends seamlessly from the wall to the ceiling because the pattern is calculated based on 3D coordinates, treated as a fully 3D pattern like actual rock veins extending through a volume.
