I had a bag, a box and a fishbowl that were all full of tiny balls of yarn left over from previous projects. I'm talking small -- too small even for making doll sweaters. Some of them could have made doll a SLIPPER, but really, how many dolls want only one slipper? I'm not changing yarns and weaving in ends in a slipper that is less than 3 inches long.
The beauty of this method is that you don't have to have 'the right amount' of yarn, they don't have to even be the same kinds of yarn, although I found out that if you're using pure, shrinkable wool with acrylics and washable wool, you could have a problem, so all yarns should at least be washable. If not, you'll be dry cleaning or hand washing a blanket!
In the zigzag pattern, you did one row at a time, going right to left as is normal in crochet, and cut off the yarn at the end of each row.
You can see where I changed colors in the gray stripe just before I ended the row... I had run out of yarn completely so I just tied the new one on. All the ends are hanging loose, like eyelashes where the color changes. The black row has one stitch that dips down into the previous row and forms a point. I even tried some shells for a couple of rows.
The great thing about this project is, it's done, the stash is busted, and it's warm when I toss it over my legs on the couch.