Snapshots of the surface density at the end of the infall phase (t = 8 kyr) for the ﹩{\dot{M}}_{{\rm{in}}}=1{0}^{-7}\,{M}_{\odot }\,{{\rm{yr}}}^{-1}﹩ models with ﹩\cos {\theta }_{0}\in [0.3,0.4]﹩ (left), [0.5, 0.6] (middle), and [0.7, 0.8] (right). As the streamer approaches the disk midplane (smaller ﹩\cos {\theta }_{0}﹩), the resulting spiral arm becomes more extended and prominent in the outer disk.