gistfile1.txt

digraph G {
    a [shape = box];
    b [shape = box];
    rem [shape = invtrapezium];
    t [shape = box];
    ab [shape=circle, fixedsize=true, width=0.3, label="x", xlabel="a<-b"];
    result [shape=circle, fixedsize=true, width=0.3,label="="];
    0 [shape=triangle];
    rt [ shape=circle, fixedsize=true, width=0.3, label="x", xlabel="r<-t"];
    bt [ shape=circle, fixedsize=true, width=0.3, label="x", xlabel="b<-t"];

    # 配線
    b -> ab;
    ab -> a;
    b -> rem;
    a -> rem;
    rem -> rt;
    rt -> t;
    0 -> result;
    b -> result;
    t -> bt;
    bt -> b;
    {rank=same; rem; 0 };
    {rank=same; a; b; ab; result};
    {rank=same; rem; bt};
}