Abstract: A first frame has a first end and a second end, two opposing first frame side walls and a first pivot pin extending laterally between the first frame side walls at the second end of the first frame. A generally planar first barrier is attached to the first pivot pin such that the first barrier is pivotal about the first pivot pin. A second frame has a primary end and a secondary end, the second frame comprising two opposing second frame side walls, each of the second frame side walls being pivotally attached at the secondary end of the second frame to one of the first frame side walls at the first end of the first frame. A second pivot pin extends laterally between the second frame side walls between the primary end and the secondary end. A generally planar second barrier is attached to the second pivot pin such that the second barrier is pivotal about the second pivot pin. The first barrier and the second barrier are positioned in an opposed manner to each other.