VWF-induced collective network formation of rPhe2561 and rTyr2561 VWF at indicated shear rates. Each image represents a composition of 20 sequential frames of a live-cell fluorescence movie taken at a frequency of 8 frames per second. By subtracting identical pixels among frames, a color-coded addition of these differential images from frame 0 (blue) to frame 20 (red) along the color scale, combined with the inverted gray-scaled background image of the start frame, allows precise detection and motion tracking of VWF-induced collective networks. Therefore, only moving networks are displayed in color enabling an exact determination of the critical shear rate. The rTyr2561-VWF variant (lower row) shows a significantly decreased critical shear rate in comparison with rPhe2561-VWF (upper row) to less than 50%. The black arrow indicates the flow direction and a scale bar corresponding to 100 µm.