Agnipurana 104.4

104.4

tribhistu kanyasāgarbhaḥ(1) śeṣo bhittiriti kvacit /
ṣoḍhābhakyethavā kṣetre bhittirbhāgaikavistarāt //

with three [parts], however, the smallest sanctum [is made], and the remainder is the wall, according to some.
Or, when the site is divided into six parts, the wall is one part in width;