I'm trying to get a setup closer to the one PJF is using. The light in this comes from a square spotlight directed at a 100% white plane on the left. I'm buying your arguments about what's going on here, AS. What looks like light reflecting onto the floor plane from the mirror spheres is likely the color "bleed" from the reflection of the light on the sphere itself, it even has the squarish shape of the plane. And what appears to be a focusing of the light through the glass sphere could be something similar at work. Still the effect is cool, regardless of the cause. This was a max rpp render (256) but only took 20 minutes. The graininess is apparently part of the process with these settings.

This is not my "second childhood". I'm not finished with the first one yet.

Time flies like an arrow; fruit flies like a banana.

"I'd like to die peacefully in my sleep like my grandfather....not screaming in terror like the passengers on his bus." - Jack Handy