SB 10.11.35
vrndavanam sampravisya
sarva-kala-sukhavaham
tatra cakrur vrajavasam
sakatair ardha-candravat
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this way they entered Vrndavana, where it is always pleasing to live in all seasons. They made a temporary place to inhabit by placing their bullock carts around them in the shape of a half moon.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
As stated in the Visnu Purana:
sakati-vata-paryantas
candrardha-kara-samsthite
And as stated in the Hari-vamsa:
kantakibhih pravrddhabhis
tatha kantakibhir drumaih
nikhatocchrita-sakhabhir
abhiguptam samantatah
There was no need to make fences all around. One side was already defended by thorn trees, and thus the thorn trees, the bullock carts and the animals encircled the inhabitants in their temporary residence.