If you purl more loosely than you knit (most knitters do), this causes problems when you work the heel of a sock. Learn a way of purling which guarantees nice snug purl stitches - also idea for ribbing and for defining the background for cables.
by Make Some wonderful
by 365SKETCHES
by Artwork Ruchika
by VECT
by YUMMY
by Classic Beader
by Quilling shapes and techniques