Lens system configurations of the 2L1S solutions. The upper and lower panels are for the close and wide solutions, respectively. The inset in each panel shows the enlarged view around the caustic located close to the source trajectory (line with an arrow). The blue dots marked M₁ and M₂ denote the positions of the binary lens components, and the bigger dot represents the heavier lens mass. Lengths are scaled to the Einstein radius. The small magenta circle on the source trajectory represents the source size scaled to the Einstein radius: ρ = θ_*/θ_E.