Examples of various velocity fields in our sample. The ¹³CO (6–5) M1 maps from the top left corner in the clockwise direction demonstrate linear, radial, hourglass-like, and outflow-like gradients, respectively. For each source, the integrated intensities are overlaid as contours with levels ranging from 20% to 80% of the peak value in steps of 20%, and the peak position is marked by a star. Finally, the FWHM of the telescope beam is shown by a hatched circle.