strict digraph M {
    "Top" [shape=box,style="rounded,filled",fillcolor="/blues5/1",label=<<b>Top</b><br align="left"/>>];
    "customers" [shape=box,style="rounded,filled",fillcolor="/blues5/2",label=<<b>customers</b><br align="left"/>>];
    "grocery" [shape=box,style="rounded,filled",fillcolor="/blues5/2",label=<<b>grocery</b><br align="left"/>>];
    "grocery.bagger0" [shape=box,style="rounded,filled",fillcolor="/blues5/3",label=<<b>bagger0</b><br align="left"/>>];
    "grocery.lane0" [shape=box,style="rounded,filled",fillcolor="/blues5/3",label=<<b>lane0..lane1</b><br align="left"/>>];
    "grocery.lane0.cashier" [shape=box,style="rounded,filled",fillcolor="/blues5/4",label=<<b>cashier</b><br align="left"/>>];

    "customers" -> "grocery" [];
    "grocery.bagger0" -> "grocery.lane0" [];
    "grocery.lane0.cashier" -> "grocery.lane0" [];
}