(a) Proper-motion angle (θ_μ) vs. P.A. angle of QSFs (θ). The solid line indicates θ_μ= θ. (b) The difference θ_μ − θ vs. the projected distance of QSFs from the explosion center. The dotted lines indicate θ_μ − θ  = ​​​​±30°. Blue symbols indicate Group 1 QSFs, while magenta symbols represent Group 2 QSFs. The error bar with an arrowhead indicates continuation beyond the plotted range for a data point with an uncertainty exceeding the axis limits.