A note on forcing triples with no forcing pairs

Chung, Graham and Wilson defined a set of graphs $\mathcal{H}$ to be forcing, if any sequence of graphs $\{G_n{\}}_{n\ge 0}$ with $\mathrm{\mid }{G}_n\mathrm{\mid }=n$ must be quasirandom, whenever $hom(H,G_n)=(p^{\mathrm{\mid }E(H)\mathrm{\mid }}+o(1))n^{\mathrm{\mid }V(H)\mathrm{\mid }}$ for every $H\in \mathcal{H}$ and some constant $p\in (0,1)$. Answering a question of Horn, attributed to Graham, a forcing set of three graphs is constructed such that no two of the three graphs are forcing as a pair.