digraph G {bgcolor="red:cyan" gradientangle=0

    subgraph cluster_0 {
        style=filled;
        color=lightgrey;
        fillcolor="blue:yellow";
        gradientangle=90;
        node [fillcolor="yellow:green" style=filled gradientangle=270] a0;
        node [fillcolor="green:red"] a1;
        node [fillcolor="red:cyan"] a2;
        node [fillcolor="cyan:blue"] a3;

        a0 -> a1 -> a2 -> a3;
        label = "process #1";
    }

    subgraph cluster_1 {
        node [fillcolor="yellow:magenta"
             style=filled gradientangle=270] b0;
        node [fillcolor="magenta:cyan"] b1;
        node [fillcolor="cyan:red"] b2;
        node [fillcolor="red:blue"] b3;

        b0 -> b1 -> b2 -> b3;
        label = "process #2";
        color=blue
        fillcolor="blue:yellow";
        style=filled;
        gradientangle=90;
    }
    start -> a0;
    start -> b0;
    a1 -> b3;
    b2 -> a3;
    a3 -> a0;
    a3 -> end;
    b3 -> end;

    start [shape=Mdiamond ,
        fillcolor="yellow:brown",
        gradientangle=90,
        style=radial];
    end [shape=Msquare,
        fillcolor="orange:blue",
        style=radial,
        gradientangle=90];
}
