digraph g{
        newrank=true;

        subgraph cluster_d{
            A -> B
        }
        subgraph cluster_v{
            C
        }
        {rank=same; A, B, C }
        B -> C    
    }

    digraph g{
        rankdir=LR;
        newrank=true;

        subgraph cluster_d{
            A -> B
        }
        subgraph cluster_v{
            C
        }
        B -> C    
    }