vermicular movement

例句：

1. 1.The spiral staircase leads up to the second floor.
   螺旋楼梯通向二楼。
2. 2. The helical growth of the tree is remarkable.
   树木的螺旋生长令人赞叹。
3. 3. The helical structure of the shell is fascinating.
   贝壳的螺旋结构非常迷人。