I used a vintage yarn I bought at an estate sale. It was an old Red Heart Baby Sport Yarn, which is a 3-ply sport weight. I had 2 skeins in pink, and 1 each in yellow and blue, so I made my blanket a 3 color stripe with a pink border.

The recommended gauge on the yarn is listed as 22s x 30r = 4 x 4 inches on a size 6 needle. Gauge is not as dire on the blanket, since size variance is acceptable. I tend to knit a loose gauge, so I used US size 5 needles (smaller needle makes my loose stitches tighter).