19:32The end of them isn't square shaped. It's actually formed inside their intestines.
19:36The nutrients are constantly squeezing and pulling that shape.
19:40Now there's another reason why they do square shaped poo's essentially. They'll leave it at the front entrance of their burrows and essentially because it's cube shaped they won't roll down the hill.
19:50But Wombats mainly do it to mark their territories so let other Wombats know that this is their home.