digraph PSSA { 
  rankdir="LR";
  node [shape="box" fontsize=14 fontname="Arial" fillcolor=white color=lightgrey style=filled];
  edge [color="#ff8000" ]
  subgraph cluster_Problem {
    label="problem analysis"
    fillcolor=lightgrey color=white style=filled fontname="Arial"
    P1 [ label="..."]
    P2 [ label="..."]
    P3 [ label="..."]
  }
  subgraph cluster_Struktur {
    label="structuring"
    fillcolor=lightgrey color=white style=filled fontname="Arial"
    St11 [ label="..."]
    St12 [ label="..."]
    St13 [ label="..."]
    St21 [ label="..."]
    St22 [ label="..."]
    St31 [ label="..."]
    St32 [ label="..."]
    St33 [ label="..."]
  }
  subgraph cluster_System {
    label="systematization"
    fillcolor=lightgrey color=white style=filled fontname="Arial"
    Sy1 [ label="..."]
    Sy2 [ label="..."]
    Sy3 [ label="..."]
    Sy4 [ label="..."]
  }
  subgraph cluster_Automatisierung {
    label="automation"
    fillcolor=lightgrey color=white style=filled fontname="Arial"
    At1 [ label="..."]
    At2 [ label="..."]
    At3 [ label="..."]
    At4 [ label="..."]
    At5 [ label="..."]
    At6 [ label="..."]
    At7 [ label="..."]
    At8 [ label="..."]
  }

  P1 -> St11
  P1 -> St12
  P1 -> St13

  P2 -> St21
  P3 -> St31
  St11 -> Sy1
  St12 -> Sy2
  St13 -> Sy3
  St21 -> Sy4
  Sy1 -> At1
  Sy1 -> At2

  Sy2 -> At3
  Sy2 -> At4
  Sy3 -> At5
  Sy3 -> At6
  Sy4 -> At7
  Sy4 -> At8
}