a Right alternating twist SZ: the rope is twisted to the right, the strand is twisted to the left, and the twist direction of the strand rope is opposite to that of the steel wire in the strand, which is called alternating twist
b Left alternating twist ZS: rope left twist, strand right twist
c right twist ZZ: right twist of rope, right twist of strand
d Left-hand twist: the rope is twisted to the left, and the strand is twisted to the left
e Right mixed twist: the rope is twisted right, some strands are left twisted, and some strands are twisted right
f Left mixed twist: the rope is twisted left, some strands are twisted right, and some strands are twisted left
