Sequences of AIA 304 and 171 Å images showing the eruption and post-eruption evolution of the filament. The erupted material shows clear helical twist at around 16:39 UT, as seen in panels c) and c1). Time-distance plots along vertical cut 5 and 6 also illustrate twisting motions of the erupted flux ropes (panel e) and e1)). The “+” symbols in panels d) and d1) track the inverse γ-shape structure with apparent crossing of the two filament legs.