[If] tumah is within a wall inside a space that is a cubed handbreadth — every story above it becomes tamei, even if there are ten [stories]. [If] an upper story [is built] over two houses [and there is tumah in the wall between the two houses] — it becomes tamei, but all the stories above it remain ta-hor. [If] there is tumah inside a dike, it penetrates directly upward and downward. [If] a tombstone is on top of an occluded grave — someone who touches its sides remains tahor, because the tumah penetrates [only] upward and downward. [But] if the place of the tumah contains a cubed handbreadth [of empty space], one who touches any part of [the tombstone] becomes tamei, because it is treated as a sealed grave. [If] huts were leaned against it — they become tamei. R’ Yehudah declares them tahor.