Knitting Projects - Scarves

A friend of mine from Purdue knows how to blow glass. So we set up a deal, that if I knitted him a scarf, he'd make me a marble. He requested black and red. The yarn is acrylic. I casted on 36 stitches on US 10 (6.0 mm) needles. I forgot to measure the width, but it is 68" (5 2/3 feet) in length. The first and lst 5 rows (or so) are garter stitch. All rows between are 3 stitches knit, 3 stitches purl, alternating, to get ribbing.