A series of five 43 GHz total (contours) and polarized (colour scale) intensity images of BL Lac with a resolution beam of 0.1 by 0.1 mas and the total intensity peak of 1.59 Jy beam⁻¹. The contours are 0.4, 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, and 51.2% of the peak plus one additional contour 96% of the same peak to localize the peak more precisely. Red linear segments within images indicate the direction of polarization; the red horizontal line mark positions of the core A0, and stationary features, A1 and A2, according to Jorstad et al. (2017). The blue line indicates a possible motion of a hypothetical knot K15.