  Generalizing a recent construction of Yang and Yu, we study to what extent
one can intersect Hassett's Noether-Lefschetz divisors $\mathcal{C}_d$ in the
moduli space of cubic fourfolds $\mathcal{C}$. In particular, we exhibit
arithmetic conditions on 20 indexes $d_1,\dots, d_{20}$ that assure that the
divisors $\mathcal{C}_{d_1},\dots,\mathcal{C}_{d_{20}}$ all intersect one
another. This allows us to produce examples of rational cubic fourfolds with an
associated K3 surface with rank 20 N\'eron-Severi group, i.e. a singular K3
surface.
