Tu panxiu embroidery is made with two threads of the same color at once. One is laid in a coil along the design; the other passes through the needle to secure it to the cloth. The paired action builds a raised, compact surface. In the national intangible-heritage description, the work is done without a frame: the embroiderer holds the fabric in one hand and guides the needle with the other.
The two lines have separate jobs but move as one operation. The laid thread forms the visible track, while the stitching thread anchors it to the ground. That construction can make the finished embroidery dense and sturdy, with a relief-like texture that catches light along its curves.
