Source

canvas2dot / dots / chord.dot

digraph G {
    subgraph cluster_1 {
        color=blue;
        mul_1[label="mul"];
        add_1[label="add"];
    }

    subgraph cluster_2 {
        color=blue;
        mul_2[label="mul"];
        add_2[label="add"];
    }

    mul_1 -> div_1;
    add_1 -> div_1;
    mul_2 -> div_2;
    add_2 -> div_2;

    div_1[label="div"];
    div_2[label="div"];
}