Regarding a pillar lying on its side in the open air, if its circumference is 24 handbreadths, it conveys ritual impurity under its side. If this isn’t the case, then the impurity extends both upwards and downwards.
Regarding an olive-sized piece of a corpse stuck to a threshold, Rabbi Eliezer rules the house unclean and Rabbi Yehoshua rules it clean. If the impurity was placed beneath the threshold, the situation follows the rule of halves. If the impurity is stuck to the lintel, the house is rendered unclean, though Rabbi Yosi rules it clean. If the impurity was in the house, one who touches the lintel is rendered unclean. Regarding one who touches the threshold, Rabbi Eliezer rules him unclean while Rabbi Yehoshua says that if he touches it from a handbreadth down, he remains clean but if from a handbreadth up, then he is rendered unclean.