Shatapatha Brahmana 4.5.1.14

4.5.1.14

tadyatpañcakapālaḥ puroḍāśo bhavati | pañcapadāḥ paṅktayo yājyānuvākyāḥ pāṅkto vai yajñastadyajñamevaitatpunarārabhate tathāsyāyātayāmā yajño bhavati tatho asmānna parāṅ bhavati

The reason why the cake is one on five potsherds, and the invitatory and offering prayers are paṅktis (verses of five feet), is that the sacrifice is fivefold. He thus takes hold again of the sacrifice, and thus that sacrifice of his is not exhausted in strength, and does not pass away from him.