digraph G {
    rankdir=LR;

    {i1 i2} -> {h1 h2 h3} -> {o1 o2};
    i1, i2, h1, h2, h3, o1, o2 [shape=circle; label="";];

    input -> hidden -> output [style=invis;];
    input, hidden, output [shape=plaintext;];
}