Three-dimensional sipes for treads

Both a mold blade (10) for forming sipes and the sipe (26) so formed in a tire tread element (24) have three dimensional portions. In the formed sipe (26), the three dimensional portion creates a constant interlocking of the opposing sipe faces. The blade (10) and the sipe (26) have at least one row of alternating polygonal shaped recesses (20,30) and protrusions (18,32). The recesses and protrusions terminate in a vertex (22,44); the vertex has a planar, or two-dimensional, configuration that is parallel to either the blade centerline or the sipe centerline.