This pattern can be found for free online at https://jessieathome.com/double-crochet-c2c/

Corner to Corner (C2C) Box Stitch has become a hot stitch over the past few years. It can be used to make a square or rectangle of any size with pretty much any yarn. Plus it is made of blocks so it can be used to create graphed images. Once you have this stitch down you can take a graphed image (such as a cross stitch pattern) and crochet it. So cool!!
Size:
varies by yarn

Yarn:
any – the following were used for the samples in this pattern:

King Cole Dollymix DK, 100% Acrylic, (25 g / 80 yds)
US G/6, 4.0 mm hook
7 blocks x 75 blocks = 4″ x 44″; (70 g / 224 yds) used

Sugar Bush Bold, 100% Wool, worsted weight, 100 g / 190 yds
US-H/8, 5.0 mm
7 blocks x 72 blocks = 4.25″ x 44″; (120 g / 228 yds) used

Hook:
varies by yarn

Gauge:
varies by yarn

Other supplies:
yarn needle

Stitches and Abbreviations:
ch – chain
dc – double crochet
sl st – slip stitch
sp(s) – space(s)
st(s) – stitch(es)