  We review the problem of flavour tracing back to the days when the standard
model was just coming together. We focus on the recently discussed new
solutions of this problem, namely models based on the discrete
$\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetry and the VEVs
hierarchy, and discuss their various phenomenological consequences. In
particular, there appears a novel feature that the solution of the flavour
problem based on the discrete flavour symmetry can provide the so-called
flavonic dark matter. This predicts a specific relation between the mass and
the symmetry-breaking scale, which can be contrasted with the standard QCD
axion.
