Patent ID: 8114132

Claim:
A device, comprising: a first superior plate having a first inferior portion; a second superior plate having a second inferior portion; a first inferior plate having a first superior portion; a second inferior plate having a second superior portion; a first joint connecting the first inferior portion of the first superior plate to the first superior portion of the first inferior plate; a second joint connecting the second inferior portion of the second superior plate to the second superior portion of the second inferior plate; a plurality of spikes located along interior portions of the first superior plate and the second superior plate and along interior portions of the first inferior plate and the second inferior plate; wherein the first and second joints are flexible; wherein a first theoretical centerline intersects the first inferior portion of the first superior plate, the first superior portion of the first inferior plate, and the first joint; wherein a second theoretical centerline intersects the second inferior portion of the second superior plate, the second superior portion of the inferior plate, and the second joint.