Left: schematic representation of the model of the molecular envelope of NGC 7027. The shells and blobs are colored according to their densities, in a logarithmic scale. The axes denote the equatorial and polar directions. Right: velocity field of the model, resulting from the combination of radial and polar components, both pointing outwards from the central star. The polar component is activated for distances to the equator greater than 1.5 × 10¹⁶ cm (the region where it is not active is indicated). The velocity of the polar blobs is purely along the polar direction.