The term 'fastens securely' can be accomplished in a variety of ways. BOLTS, nails, ties, and mortises are all solutions to this term. BOLTS are cylindrical pieces of metal with a head on one end that are inserted into two pieces of material and secured with a nut. Nails are thin pieces of metal with a pointed tip that are driven into two pieces of material to hold them together. Ties are strips of material that are used to bind two objects together. Mortises are recesses cut into one piece of material that fit around a tenon, which is a projection on another piece of material, to hold the two pieces together. All of these solutions can be used to fasten two pieces of material securely.