  Azimuthal angle dependence of the pion source radii has been measured
applying the event shape engineering technique at the PHENIX experiment. When
events with higher magnitude of second-order flow vector are selected, the
oscillation of the source radii is enhanced as well as $v_2$ which leads to the
enhancement of the measured final source eccentricity. The event twist effect
in the spatial source distribution in the final state has been also explored
with AMPT model. Results indicate a possible twisted source due to the initial
longitudinal fluctuations.
