  We present a case study of the solar flare (SOL2001-10-02T17:31) that showed
quasi-periodic pulsations (QPPs) in hard X-rays with two simultaneously excited
periods, P_1 = 26-31 s and P_2 = 110 s. Complete evolution of the flare
recorded by the Yohkoh telescopes, together with the patrol SOHO/EIT images,
allowed us to identify magnetic structures responsible for particular periods
and to propose an overall scenario which is consistent with the available
observations. Namely, we suggest that emerging magnetic flux initiated the
reconnection with legs of a large arcade of coronal loops that had been present
in an active region for several days. The reconnection excited MHD oscillations
in both magnetic structures simultaneously: period P_1 was generated in the
emerging loop and in a loop being a result of the reconnection; period P_2
occurred in the arcade. Both resonators produced photons of different spectra.
We anticipate that multiperiodicity in hard X-rays can be a common feature of
flare hybrids, i.e. the events, in which magnetic structures of different sizes
interact.
