Both a mold blade for forming sipes and the sipe so formed in a tire tread
element have three dimensional portions. In the formed sipe, the three
dimensional portion creates a constant interlocking of the opposing sipe
faces. The blade and the sipe have at least one row of alternating
polygonal shaped recesses and protrusions. The recesses and protrusions
terminate in a vertex; the vertex has a planar, or two-dimensional,
configuration that is parallel to either-the blade centerline or the sipe
centerline.