Pattern Description from Knitting Rules!: “There are two ways to go about a triangular shawl, basically speaking. Either you start with your maximum number of stitches and decrease or you start with a stitch or two and increase. I adore a shawl that gets smaller with each row. It’s veyr good for the morale, but the downside is that you’d better be sure that you have enough yarn or there isn’t going to be a triangle, as the shape is forming as you go. (Note to self: Find out technical term for shape created when you don’t knit the tip of a triangle. Could be an idea if it had the right name.) When a shawl is knit in the increasing manner, if you run out of yarn, you can just cast off; the triangle shape is present (if tiny) from the beginning. With a shawl knit in the decreasing manner, all you can do if you run out of yarn is go for the chocolate.”

This pattern may be found on pages 180-181 of Knitting Rules!