Granny square apparel is a cyclical fashion that peaked in the 1970’s. As Stitch ‘n Bitch series author Debbie Stoller describes:

If you grew up in the seventies, as I did, you might fear the granny square–if only because, for a while, clothing was made of nothing else. Granny square vests, granny square shorts, granny square hats. Heck, I bet there was some kid out there who was forced to go to school wearing granny square underwear.

Although particular color and pattern schemes for granny squares change with time, this class of motif is a staple among crocheters. Multicolor granny squares are an effective way to use up small amounts of yarn left over from other projects and basic granny square motifs do not require advanced skills to execute.

Soure: Wikipedi