  Multi-frequency forcing of systems undergoing a Hopf bifurcation to spatially
homogeneous oscillations is investigated using a complex Ginzburg-Landau
equation that systematically captures weak forcing functions that
simultaneously hit the 1:1-, the 1:2-, and the 1:3-resonance. Weakly nonlinear
analysis shows that generically the forcing function can be tuned such that
resonant triad interactions with weakly damped modes stabilize subharmonic
quasipatterns with 4-fold and 5-fold rotational symmetry. In simulations
starting from random initial conditions domains of these quasi-patterns compete
and yield complex, slowly ordering patterns.
