Time–distance diagrams in H_α −0.8 Å and +0.4 Å, He I 10830 ± 0.4 Å, AIA 304 and 171 Å for the cutting strips along the long loop 1 and long loop 2. Note that the red-wing absorption features in He I 10830 Å and H_α move eastward along the long loop 1, as indicated by the arrow in the Figure 3(a1). The mass flow inside the long loop 2 is also unidirectional and only contains blue-wing absorption features.