This is an idea i had a while ago but didn't have the money for. So instead I did it for my sister and our friend. What I did was buy 2 sweaters (same size and style, only difference being the colour), cut them in half the exact same way, then sew them to the other's other half. I had to be careful so that I would leave the drawstring in tact and still have it work. Here are the pictures of the final product.