A Voronoi diagram colored with a radial gradient centered on each cell's site. The luminance of each point is proportional to the cost of reaching the nearest site (the darker the color, the higher the cost).
forked from nitaku's block: Cushion Voronoi
https://d3js.org/d3.v4.min.js
https://d3js.org/d3-selection-multi.v0.4.min.js