Spirals traces in polar coordinates for the same observation (SPHERE 2015) at different wavelengths. Theta is the angle measured counterclockwise from north of the central star. Contrary to Fig. 3, images were not deprojected here. S3 is not included as it was not well detected in all wavelength bands. In black, labeled Δr, the typical trace uncertainty, not shown on each data point to improve readability.