An illustration of how an arbitrary scalar value changes in 3D space with distance from a point source. For example, if the black bead at the center were a heat source, the colored beads depict the way temperature would vary with distance. This mathematic scenario arises frequently in nature: the intensity of light about a light source, the electrostatic field about a charged point, the gravitational pull about a massive object, and so on. Clear acrylic beads of varying sizes were dyed with illustration marker refill ink. These were then mounted on acrylic rods inserted into a wooden base, separated by clear plastic cocktail straws cut to precise lengths using a model railroad chopper and 3D printed jigs.