This is all happening outside the mouse house. On the left, you can see the white thing. That's their food. They can crawl up and out of their house to take a bite of the white mouse food. Over on the right, the green thing is the roof to their house. The oxygen tank is hooked to the top of their roof. It's there in case a mouse has trouble breathing. The mouse can breathe some oxygen that will go through a clear tube into its nose, just like grandpa. If they run out of oxygen in the first tank, they can use the second tank. The mice are living in their house under the green roof.