As well as knitting, crochet basic technique is to thread into an existing node to create a new node. Different from knitting, there is only one knot hole that opens when already crochet (except when making lace Tunisia)
I never knew this crochet skills when I was a teenager. When it joined the trend with friends using the crochet hooks. Not much I learned at that time, until then I completely forgot how to crochet. The only thing I remember was the thread and hooks used.
I hope this app can inspire you