Shiva Purana
तालपत्रं समादाय तत्समायामविस्तरम्॥ तस्मिन्भागान्प्रकुर्वीत त्रयोदशसमां कलाम्॥ ३॥
Make small squares within the width of a palm-leaf each. Thus there shall be thirteen equal squares in each column.
english translation
tAlapatraM samAdAya tatsamAyAmavistaram॥ tasminbhAgAnprakurvIta trayodazasamAM kalAm॥ 3॥
hk transliteration by Sanscript