Using d3-voronoi on a cylinder.
The solution is to have two copies of each site, on the right-hand side and left-hand side of the original.
The n first cells and n first sites are the originals.
We add a shadow property to copies of sites, and filter out links that have only shadow copies.
Apply twice for a Toric Voronoi.
Made by Philippe Rivière from mbostock‘s block: Canvas Voronoi