Left: sketch of V766 Cen with the photosphere, MOLsphere, Na i shell (Wittkowski et al. 2017a), and the companion at positions from C14 (epoch C) and our epochs EII and EIII. Also shown is a plausible Keplerian orbit for a fixed period of 1304 d and semi-major axis of 3 mas. The circles indicate the positions at our epochs. Right: illustration of an in-contact system with our radius ratio, where the companion is next to the star and we clearly see the Roche lobes (phase 0.0, top), and in front of the primary (phase 0.25, bottom). These example phases do not correspond to the observed intermediate phases in the left panel.