Cro-hooking, cro-knitting, double hook crochet, "crochet on the double"? - double crochet hook

Cro-hook Cro-as knitting, crochet, and double-click "crochet on the double" is a variant of the Afghan crocheted Tunisia.

Is there a good side who teach them? I googled and instructions are amazing.

In addition, certain trends are fairly free and towels?