Figure 8.

Stitched photomicrographs of the manufacturing marks at different regions of a single straw (which had been cut lengthwise) from the packet labeled “ZONE-1”. The distances between regions I to II, II to III, and III to IV were 3 cm, 2 cm, and 1 cm, respectively. Most of the striations were relatively straight and parallel to the extrusion direction, and were consequently well-aligned across the four regions. Some of the striations were, however, either wavy or produced at an angle to the extrusion direction; these were typically observed as being slightly displaced from a region to another. In general, better agreements were observed for regions that were nearer to each other.