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Concrete and other reinforced materials can be made several times tougher by
using reinforcing wires or fibres shaped like the bones you see in cartoons. The
surrounding matrix grips the bumps on the ends much better than smooth wire,
just as people in a tug of war hold onto knots much better than a straight piece
of rope. By adding 2.5-centimetre bone-shaped wire segments to concrete,
Theodore Zhu of the Los Alamos National Laboratory in New Mexico increased its
resistance to breakage by a factor of 94鈥攁n increase 3.7 times higher than
would be possible with straight filaments.