Schematic presentation of the continuum polarization in SN2021yja (observer’s view) created by a bipolar explosion. At early phases, the photosphere is extended vertically due to the energetic ejecta component, which creates the first vertical polarization component (Phase 1). Then, the shape of the photosphere is crushed horizontally because of the withdrawal of the photosphere in the energetic component, which creates the second horizontal polarization component (Phase 2). This explains the rotation of the observed polarization angle. The polarization vectors of important individual photons from the photosphere are indicated with small arrows. The large arrows show the net polarization vectors of all the photons.