[If] one assembled three feet upon the ground and joined them with clay so that he could set the pot on top of them, [this makeshift stove] is tamei. [If] one affixed three nails into the ground so that he could set the pot on top of them, even though he fashioned a place at the top of [this makeshift stove] for the pot to rest, it is tahor. [If] one made two stones into a stove and joined them with clay, it is tamei. R’ Yehudah rules [it] tahor until he makes a third [stone] or until he places [the stove] near a wall. [If] one [stone was joined] with clay and one was not [joined] with clay, it is tahor.