digraph G {
rankdir=LR
a[label="1/2 (H)"];
b[label="1/4 (HH)"];
c[label="1/8 (HHH)"];
d[label="1/16 (HHHH)"];
e[label="1/32 (HHHHH)"];
a->b;
b->c;
c->d;
d->e;
}