Matsya Purana 264.37

264.37

lekhā trayantu kartavyaṃ yavāṣṭāntarasaṃyutam.
na sthūlaṃ na kṛśaṃ tadvanna vakttraṃ chedavarjitam .. 264.36

The image should be divided into three parts and afterwards three lines at a distance of eight Yavas from one another should be drawn which should be broad, thin and crooked They should not be broken (i e., should be continuous)—35 36