Chapter 1

    graph TD;
        A-->B;
        A-->C;
        B-->D;
        C-->D;

Chapter 1

    graph TD;
        E-->F;
        E-->G;
        F-->H;
        G-->H;

Chapter 1

Chapter 3

    graph TD;
        E-->F;
        E-->G;
        F-->H;
        G-->H;

chapter 3