6.7 GHz maser spectra and spatial structures during all epochs of EVN observations. Coloured lines show the cross-correlated VLBI spectra and colour corresponds to velocity of maser cloudlets shown in the bottom panels. The emission is filtered out by the EVN beam by more than 40–60% for most of the spectral features. The size of each circle is scaled with the logarithm of peak flux density. The symbol of grey star with the error bars indicates the position of the 1.3 mm continuum emission peak (Palau et al. 2013).