  Flavour symmetries are fundamental tools in the search for an explanation to
the flavour puzzle: fermion mass hierarchies, the neutrino mass ordering, the
differences between the mixing matrices in the quark and lepton sector, can all
find an explanation in models where the fermion generations undergo specific
geometric relations. An overview on the implementation of continuous symmetries
in the flavour sector is presented here, focussing on the lepton sector.
