From the website:
“This garter stitch ball is about 4 or 4.5 inches in diameter -- about the size of a grapefruit -- and is shaped by short rows. It’s a good for using up odds and ends of yarns of different colors. Each section takes about 4 yards of yarn.
This is a perfect toy for a child about a year old, just at the age they begin to walk -- it’s soft, easy to hold onto, machine washable and dryable (if made and stuffed with synthetic materials), and can be made in bright, attractive colors.

The pattern is based on a 10-section ball pattern posted by Valle to the Knitlist at Christmastime, 1995. The original pattern is archived at Emily Way’s Wool Works. One reason I changed it to 12 sections was because 12 is divisible by more numbers, so the possibilities for color combinations are increased. My favorite (shown here in the inside-out version) is red - white - blue - white. Also see photos of both versions, the “right-side out” and the “inside-out,” in progress.

And other people have been inspired to create their own variations on the yarnball! Take a look at a Moon and a Swirl.

Please notice that although I describe this ball as being knitted in “sections,” the sections are not separate pieces, just one color wedge after another! The photos of the in-progress yarnballs show what I mean.“