Prograde spin-up in the collapse phase of the streaming instability, visualized for a wide range of orbital separations, asteroid sizes and initial conditions. The dashed horizontal lines tangent to the circles represent the rotation prior to collapse, while the arrows indicate the magnitude of prograde spin-up. The ringed circles represent the size of the asteroid that forms, and their colors show the total center-of-mass displacement during the collapse δa. The systems within the dark red lines represent cases where there is insufficient rotational angular momentum to form binaries (ω_spin < ω_crit). The systems above and below the red lines show the formation of prograde and retrograde binaries, respectively. The preference for prograde binary formation is clearly visible, especially in the outer disk.