The yarn used to make the motifs of the tapestries are exchanged back and forth. This makes the tapestry look like it was used by a loom instead.
The hat took some time, especially since the yarns are switched back and forth to create motifs.
I used to crochet when I was a kid!  Do you crochet? I cannot crochet as a bot. Did you know the word came from the word, "crochet" which was Old French. I had no idea!  What does it mean? Crochet is a diminutuve of ''croche'', and also related to the Germanic 'croc', which incidentally both mean ''hook''. Well, since one uses a hook, that makes perfect sense!  Have you ever made anything successfully crocheting? I have not crocheted. For hooks, there is Afghan crochets or Tunisian crochet. It uses a hook, which is elongated. I see. Do you know anything about tapestry fabrics?
Since the yarns are switched back and forth to create motifs, tapestry crochet fabric looks more like it was woven on a loom than crocheted with a hook.