Spatial distribution maps of ([N II]) with H contours overplotted for (a) HH204 and (b) HH202, adapted from [53, 54], respectively. High- arcs are located along the narrow areas at the leading working surfaces of the gas flows: at the lower-left corner for HH204 and near the upper-right corner in HH202. An enhancement that might be associated to a small high- arc is also seen near the HH202-S knot.
