digraph "" {
        md [label="document source\n(Markdown)"];
        md [shape=box];

        bindings [label="bindings file\n(YAML)"];
        bindings [shape=box];

        impl [label="step implementations\n(Python, Rust, ...)"]
        impl [shape=box];

        docgen [label="Doc generator"];
        docgen [shape=ellipse];

        codegen [label="Code generator"];
        codegen [shape=ellipse];

        pdf [label="PDF/HTML document"]
        pdf [shape=diamond];

        testprog [label="Test program\n(generated)"]
        testprog [shape=box];

        report [label="Test report"]
        report [shape=diamond];

        md -> docgen;
        bindings -> docgen;
        docgen -> pdf;

        md -> codegen;
        bindings -> codegen;
        impl -> codegen;
        codegen -> testprog;

        testprog -> report;
}