This is the first in what I hope to be many granny square style designs. I love making granny squares because you can use whatever you have on hand. With projects like these it is more about the pattern than the materials you use so don't worry if yours is a little different. Use whatever you want to make this pattern.
I called it the Arrow because that is what it reminds me of.

Step 1: Materials You Will Need.

Like most crochet projects you will need
Scissors
A crochet hook (I used an H, but you could use what works best for you and your yarn.)
Two colors of yarn, (This is worsted, but you could use whatever.)

Step 2: Glossary of Terms.

This is always important.

Ch: chain
Sl st: slip stitch
Dc: double crochet

Step 3: Starting the Square

Ch 4 and connect with a sl st. Making a hole to work your stitches in.
Ch 3 (counts as first) and Dc 15 into the hole.
Do not turn your work.

Step 4: Working the First Color

Ch 3 and dc in the same space.
Dc 1 in the next 3 stitches, dc 2 ch 1 dc 1 in next stitch, Dc 1 in next 3 stitches.
In the next stitch dc 2.
Do not finish off your last Dc. Leave the last two loops un-worked.

Step 5: Working the Second Color

To pick up the next color pull your second color up through the two loops of your previous dc.
Ch 1 and dc 2 in the same space.
Dc 1 in next three stitches, dc 2 ch 1 dc 2 in next stitch, dc 1 in next 3 stitches. Dc 2 in the same stitch as the first double crochet of the first color, ch 1 and sl st to the first stitch.

Turn your work.
Do not cut the yarn of either color.

Step 6: Working the Next Round.

Keeping the second color attached sl st into the last ch space you made.
Ch 3 and dc 1 in the ch space.
Work all Dc and in the ch space work, dc 2 ch 1 dc 2, to the next multicolored corner.
Dc 2 and pick up the first color the same way you picked up the color previously.
Ch 2, work all Dc and in ch space work, dc 2 ch 1 dc 2, to the next multicolored corner, Dc 2 in the first ch space, ch 1 and sl st to first.

Turn your work!
Repeat this step as many times as you like to get the size you want.