This version seems to cause more 'rivers' in the points than the original (easier to see if you turn off the lines). I think throwing in some radius variation helps. Here was my fiddling, https://observablehq.com/@jrus/bridson-fork/2 we have been discussing at https://d3js.zulipchat.com/#narrow/stream/273725-D3/topic/d3-force.2C.20fill.20a.20shape