Layering rugs is a great design trick to add depth and contrast to any space. There are numerous reasons to layer rugs. One reason is size - some rugs may not come in the large size required for a room or seating area or you may have found the perfect vintage rug but it is too small for your area. By layering your smaller rug over a larger rug you still get the impact of that perfect rug for the space and don't have to worry about the scale being off. Another great reason to layer rugs is for texture and depth. Hides are a great example of this - they tend to be somewhat thin and not too cushy, but by layering them you get the beautiful addition of a hide to your room and still the comforts of soft padding under foot.
Below are some of my favorite examples of layered rugs - you can see this can be done with any design style.