This pattern is for knit slippers, but I can totally see using a wool sweater and cutting and serging slippers from it! Home Slippers - DIY. this is knitting, but I bet I could use this to crochet some
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!