Hi Marie, I do not know if there is a written pattern for this, someone showed this to me when I was learning. I just add the next color when I run out of yarn, I am sure you could make it neater if you wanted to but I am one of those people that just CAN'T throw out any yarn, here it is:
Use any size hook
To Begin, ch 2, in 2nd chain from hook do sc, hdc, sc. Ch 1 turn.
2nd row: sc, hdc in 1st sc, sc in next hdc, and in last sc do hdc, sc.ch 1 turn at end of every row.
Basically you increase on each end by putting a sc and a hdc in the 1st and last stitch and when working across every sc on previous row gets a hdc, and every hdc on prvious row gets a sc. Keep going until it is the width you want (it will be a triangle shape) now start to decrease: pull up a loop in 1st 2 stitches, yo pull thru all loops on hook, decrease made. Work in pattern across to last 2 stitches, pull up a loop in next stitch, pull up a loop in last stitch, yo pull thru all loops, decrease made in other end. Continue to decrease 1 on each end of row until you have 3 stitches left, pull up a loop in each of the 3 stitches, you pull thru all three, end off, crochet around outside.
You can make this as big or little as you want it.