The ball was white/light gray. It has the surface texture of plaster of Paris, but it is somewhat lighter than would be appropriate for its canteloupe-like size.
I don’t think I actually pictured a whole person as pushing the ball, more likely it was a disembodied hand or the general sensation of pushing it myself.
I remember being specifically intrigued that I pictured the ball rolling back towards the center of the table and pondering why I had chosen the table to be slightly concave. I don’t remember more attributes of the table, but I have the feeling that has more to do with inattention to its details rather than not picturing them at the time.
I imagine that, based on the framing of the story, my interpretation was to picture the sphere as a literal entity, but the person as the “concept of a push”… The table probably lied somewhere in the middle.
An electric blanket is one of the best ways to warm up when you’re “chilled to the bone”. Layer them between normal blankets to make the most of the heat and keep them clean, and you can get whole body heat for a tenth the cost of even a little space heater.