digraph {
"NODE_23" [style="filled" fillcolor="red" label="task fence"]
subgraph cluster_section_1 {
     color=black;
    style=dashed
    label="foo"
    "NODE_13"
    "NODE_3"
} // end subgraph cluster_section_1
 "NODE_13" -> "NODE_23"
"NODE_3" -> "NODE_13"
"NODE_13" [style="filled" fillcolor="white" label="bar"]
"NODE_3" [style="filled" fillcolor="white" label="bar"]
}