This can be a very confusing crochet technique. It took me a while to figure it out. The squiggles are made on a crocheted open mesh. I have seen this technique (by my grandmother) used to make rugs, hot mats, place mats, pillows, etc.
Crochet Rug Technique - crochet your mesh background then add rows of double crochet to the top. The different design possibilities of this technique are absolutely endless.-Could also crochet the mesh background as a base for a rag rug!