concentrate
If true, use edge concentrators
type: bool, default: false
This merges multiedges into a single edge and causes partially parallel
edges to share part of their paths. The latter feature is not yet available
outside of dot.
Only works for non-contiguous nodes.
      
        Example
      
    
  
  digraph {
    concentrate=true
    a -> b [label="1"]
    c -> b
    d -> b
}- Graphs