Natyashastra
समन्तस्तश्च कर्तव्यं हस्ता षोडश मण्डलम् । द्वाराणि चात्र कुर्वीत विधानेन चतुर्दिशम् ॥ २२॥
All around, a Maṇḍala measuring sixteen hands should be made, and doors should be created in it according to the prescribed method, facing the four directions.
english translation
samantastazca kartavyaM hastA SoDaza maNDalam । dvArANi cAtra kurvIta vidhAnena caturdizam ॥ 22॥
hk transliteration by Sanscript