First, I grafted the Voronoi output.
Then inside the cluster, I added a Line component (yellow group) using the same inputs as the Distance component just to see what it was measuring. It was not what you wanted so I added a couple of PShift (Shift Paths) components and a Partition component (an impatient and desperate move), and finally skipped the components in the purple group because it wasn’t fun anymore.
voronoi_contours_2020JFeb14a.gh (28.9 KB)