Yantras or Mechanical Contrivances in Ancient India c2.184

c2.184

After speaking again of the *Bījas* or constituent elements and the wonder and pleasure of these yantras, Bhoja refers to the *Sūtradhāras* or chief architects who do these; their qualifications are set forth as: (1) traditionally handed-down knowledge, (2) skill combined with schooling under masters, (3) practice and application, and (4) imagination. (85-87).