When you knit through the back of the loop, the stitches are twisted at the base. Learn how to twist your stitches to knit the prettiest ribbing.
Purl stitches - Rachel Henri crochet design
Knit Together Twisted Stitch: Twisted Knit Stitch and Twisted Purl Stitch
How to knit the 2x2 Backloop Rib - The Blog - US/UK
Simple picture comparison of correct vs twisted knit stitches- hope this helps to see the difference! (Visual for both front and back loop knitting) : r/knitting
How to Knit: The Ultimate Step by Step Guide
Crystal Lattice / DROPS 231-24 - Free knitting patterns by DROPS Design
Tutorial - Twisted Stitches - Knit and Purl Through the Back Loop (ktbl, ptbl) - Stitches n Scraps
Am I twisting? : r/knitting
Tutorial - Twisted Stitches - Knit and Purl Through the Back Loop (ktbl, ptbl) - Stitches n Scraps