幺 ㄧㄠ yāo 并 ㄅㄧㄥ ˋ bìng 矢 ㄕ ˇ shǐ 么 ㄧㄠ yāo 並 ㄅㄧㄥ ˋ bìng 矢 ㄕ ˇ shǐ idemfactor (expressing a vector as sum of its three orthogonal projections)