Embodiments are disclosed of an apparatus with a first planar cutter including a center and a plurality of through-holes and a second planar cutter positioned on the first planar cutter and including a center and a plurality of through-holes. An axle passes through the center of the first planar cutter and is coupled to the center of the second planar cutter, so that rotation of the axle produces rotation of the second planar cutter relative to the first planar cutter. At least the surface of one of the first planar cutter and the second planar cutter is made of a friction-reducing material.
