Ohalos 3:3

Let’s say that a reviis of blood was poured out in the air. If it landed on an incline and one overshadowed part of it, he is ritually clean; if the blood collected in a hollow or congealed, he is ritually unclean. If the blood was poured on a threshold that inclined into or out of the house and the house overshadowed it, then the things in the house are ritually clean. If the blood collected in a hollow or congealed, then the things in the house are rendered unclean. Every part of a corpse conveys ritual impurity except for the teeth, hair and nails. When they are connected to a corpse, however, these parts are all unclean.

Ohalos 3:4

Continuing from the previous mishna: if the corpse was outside a house and its hair was inside, the house is rendered unclean. Let’s say that a bone had an olive-sized piece of flesh on it. If part of it was brought into a house and the house overshadowed it, then the things in the house are rendered unclean. Let’s say that two bones each had half an olive-sized piece of flesh on them. If parts of them were brought into a house and the house overshadowed them, then the things in the house are rendered unclean. However, if the pieces of flesh were put onto the bones by a person, the things in the house remain ritually clean because connections made by human beings are not real connections.