4x6 rugs are perfect for filling in a room. They are great for behind a sofa that has plenty of empty space or at the foot of your bed. Just put about 1/4" of the rug under the bed and leave the rest sticking out. You can do the same for your desk at work or in your office.
Placing the correct size rug in your space is as important as choosing the right color or pattern. A rug that it is too small will shift the balance of the room unfavorably. A rug that is too big, especially in open floor plans, may put the area designations off. There are a few rules of thumb, but a picture says it better. Use these handy guides by Interior Designer Lisa Ferguson to make the best choice.