digraph G {
    layout="neato"
    // scale things down for example
    size="5,5" 
    rankdir=TD
    ranksep=1
    nodesep=1

    node [shape=box]

    top[pos="5,10!", width=5, height=2]

    left1[pos="3.5,7!", width=2, height=2]
    left2[pos="3.5,4!", width=2, height=2]
    
    right[pos="6.5,5.5!", width=2, height=5]

    bottom[pos="5,1!", width=5, height=2]


    top->left1
    top->right

    left1->left2
    left1->right
    left2->right

    left2->bottom
    right->bottom
}