Natyashastra
अथ बाह्यप्रयोगेषु प्रेक्षागृहविवर्जिते । विदिक्ष्वपि भवेद्रङ्गः कदाचिद् भर्तुराज्ञया ॥ ६४॥
In the case of external performances, when the stage is not available, the performance may, at times, be conducted in any direction, as per the command of the king.
english translation
atha bAhyaprayogeSu prekSAgRhavivarjite । vidikSvapi bhavedraGgaH kadAcid bharturAjJayA ॥ 64॥
hk transliteration by Sanscript