諸經要集 3.36

3.36

又三千威儀云。遶塔有五事。一低頭視地。二不得蹈䖝。三不得左右顧視。四不得唾塔前地上。五不得中住與人語。

Furthermore, the Three Thousand Rules of Deportment states: 'Circumambulating a stupa involves five matters: first, lowering the head to look at the ground; second, not stepping on insects; third, not looking left and right; fourth, not spitting on the ground in front of the stupa; fifth, not stopping in the middle to speak with others.'