when my daughter was 12 she made her first throw sized quilt out of an animal panel (of giraffes and zebras), and a simple alternating block. She loved it, but when it was done, she wanted it to be a bed spread. we measured how far she wanted the sides to be on her bed (18 inches) and then we added "jelly roll strips" in fabric and colors that coordinated with the panel / throw. It turned out lovely and still looks good 15 years later. We had no rules....just a dream and then made a plan.