overlapping stitch made by starting next stitch at middle of preceding one
动词 backstitch:
do backstitches
backstitch详细解释
back.stitch n.（名词）A stitch made by inserting the needle at the midpoint of a preceding stitch so that the stitches overlap by half lengths.回针缝：在先前缝的一针中间加缝的一针，以便使针脚的交错重叠为原来长度的一半 【引伸】 back.stitch. v.（动词）
