It turns out that the trick was to simplify. In fact, the easiest thing to do was to create a series of small moving lights, that only rendered on the floor. This creates the moving lights that I was looking for. This shows what I was looking for.

[![enter image description here][1]][1]

How I achieved this:

1. Create a game object that periodically creates small light sources that move just above the floor.
2. The floor was already on it's own render layer. I specified the light to only affect that layer. I might change my mind on this later, but for now, I like the effect.
3. Apply a slight velocity to the objects, some random color, and away they go!

The code looks something like this:

    GameObject obj = new GameObject();
    obj.transform.position = startLocation;

    Light light = obj.AddComponent<Light>();
    light.type = LightType.Point;
    light.intensity = Random.Range(probeMinIntensity, probeMaxIntensity);
    light.cullingMask = 0x1;
    light.bounceIntensity = 0f;

    Rigidbody rigid = obj.AddComponent<Rigidbody>();
    rigid.useGravity = false;
    rigid.velocity = new Vector3(0, 0, 1);

Of course, there's still more work to do, but this was more than enough to get me over the hurdle. Thanks! [1]: https://i.sstatic.net/OICTX.png

It turns out that the trick was to simplify. @Phillip provided me with a trick, that the easiest thing to do was to create a series of small moving lights, that only rendered on the floor. This creates the moving lights that I was looking for. This shows what I was looking for.

[![enter image description here][1]][1]

How I achieved this:

1. Create a game object that periodically creates small light sources that move just above the floor.
2. The floor was already on it's own render layer. I specified the light to only affect that layer. I might change my mind on this later, but for now, I like the effect.
3. Apply a slight velocity to the objects, some random color, and away they go!

The code looks something like this:

    GameObject obj = new GameObject();
    obj.transform.position = startLocation;

    Light light = obj.AddComponent<Light>();
    light.type = LightType.Point;
    light.intensity = Random.Range(probeMinIntensity, probeMaxIntensity);
    light.cullingMask = 0x1;
    light.bounceIntensity = 0f;

    Rigidbody rigid = obj.AddComponent<Rigidbody>();
    rigid.useGravity = false;
    rigid.velocity = new Vector3(0, 0, 1);

Of course, there's still more work to do, but this was more than enough to get me over the hurdle. Thanks! [1]: https://i.sstatic.net/OICTX.png