Lens system configurations in the central magnification region for the three 2L1S solutions. Notations are the same as those in Fig. 4. The two orange circles represent the source positions at the times of the major anomalies at t₁ and t₂ that are marked in Figs. 1 and 3. The size of the circle is scaled to the source size. In the case of solution A, for which the source size cannot be securely measured, the radius of the circle is set to that of the best-fit value.