A technique manages an online meeting. and a 2,2-dimethylbutane pressure of 60 torr. The power line includes a first conductor disposed along the first direction and a second conductor disposed along a second direction that intersects the first direction. At least one of the first stepping surface and the plurality of first side surfaces has a male connector portion. At least one sensor is disposed at each of the spinning places to detect at least one measurable property correlated with fiber mass per unit of length. Iron receiving surfaces of the front and rear parts of the torso are covered with cushioning sheet materials and long and thin bags expanded by gas are attached to both sides of the front and rear sheet materials over substantially the entire longitudinal length of the sheet materials.