digraph G {
  node [ shape = "circle" ];
  cc [ label = "C2 server"; shape = "box" ];
  {
    rank = same;
    b1 [ label = "1" ];
    b2 [ label = "2" ];
    b3 [ label = "3" ];
    b4 [ label = "4" ];
  }

  cc -> b1 [ dir = "back" ];
  cc -> b2 [ dir = "back" ];
  cc -> b3 [ dir = "back" ];
  cc -> b4 [ dir = "back" ];
}