Full Stokes 229 GHz ALMA light curves of Sgr A^* obtained on 2017 Apr. 6, 7, and 11. Top row: linear polarization represented on a 𝒬 − 𝒰 plane. The color of the curve indicates the time from the beginning of the observation. Crosses “+” show the locations of the daily mean linear polarization with the EVPA . The pattern observed on 2017 Apr. 11 suggests the presence of coherent clockwise 𝒬 − 𝒰 loops, emphasized with arrows. Bottom rows: full Stokes Sgr A^* light curves. On Apr. 11, ALMA started observing immediately after the X-ray flare (gray band region). Chandra X-ray data are plotted in counts per second and were arbitrarily scaled. The red-shaded region corresponds to the period in which polarimetric loops are apparent.