This pattern uses just one crochet stitch - Treble Crochet (this is called a Double Crochet in the US).
6-Day Kid Crochet Blanket Download free pattern!
List of free stitch patterns using only knit and purl stitches for knitters of all levels. All with pictures and full patterns. Easy to follow instructions and easy to knit. | knitpurlstitches.com
Over 50 patterns are worked using only knit and purl stitches (Update 11/2015)
Ravelry: Ten Stitch Corner pattern by Frankie Brown
This addition to my Ten Stitch family of patterns is knitted one corner at a time, working from the outside in. The knitting is simple garter stitch; ten stitch wide strips are shaped with short rows and joined to the blanket as you knit.