Wu Collection, Lower Volume Radical: Stone (shí) Page 835, Entry 16 According to Collection of Rhymes (Jiyun), pronounced tuan. A personal name. There was a person in the State of Zheng named Stone Brick. Also written as the variant form for brick. According to Examination of Ancient History (Gushi Kao), Wu Cao invented the brick. In the History of the Later Han (Hou Hanshu), Biography of Heroic Women, the wife of Cao Shishu stated in the Admonitions for Internal Assistance (Neizhu Xun) that in ancient times, when a daughter was born, after three days she was placed beneath the bed, given a spindle and a brick to play with, and offerings were made in fasting and prayer. Also, according to Collection of Rhymes (Jiyun), pronounced tuo. The appearance of being round.