Vertex:
  v0: {}
  v1: {label: width=2}
  v2: {label: width=4}
  v3: {label: width=1.1}

Edge:
  e1: 
    classname: BasicStrokeEdge
    params:
      v1: v0
      v2: v1
      width: 2

  e2: 
    classname: BasicStrokeEdge
    params:
      v1: v0
      v2: v2
      width: 4

  e3: 
    classname: BasicStrokeEdge
    params: 
      v1: v0
      v2: v3
      width: 1.1
