digraph OL {
    fontname=arial;
    style=filled;
    node [fontname=arial, shape=box, style=filled, color=grey80];
    edge [fontname=arial, fontsize=10, dir=both];
    
    subgraph cluster0 {
        color=grey90;
        POE [ label="POE" ];
        POE_R [ label="(Addressing | Routing | Monitoring)", color=orange ];
        Wheels -> POE -> Selects;
    }
    OL1 [ label="Object layer" ];
    OL2 [ label="Other object layer" ];


    IKC [ label="IKC"];
    ROUTE2 [ label="Stem-compatibility"];
    
    POE2 [ label="Remote kernel"];

    OL2 -> POE_R;
    OL1 -> POE_R;
    POE_R -> IKC -> POE2;
    POE_R -> ROUTE2 -> Stem ;
    POE -> POE_R;

}