Comment 11 for bug 171901

Attached is an updated version of the pattern. The definition of the border has been modified to allow for the possibility of a completely smooth transition from one pattern to the next at the edges.
- choose zero border for a discontinuous edge.
- choose a positive border to replicate the pattern of seed points when generating the diagram, which will lead to a smooth join at the edges if the border is wide enough. To achieve smoothness, it will probably be necessary to make the border a bit larger than the average cell size, maybe twice the cell size.
- choose a negative border to reduce the size of the pattern and get a sparse region at the edges.