premise: A lab dog is standing on a fallen tree trunk with a guy in the background. hypothesis: the animal is sitting under tree.
contradiction: A dog cannot be standing on a fallen tree trunk and sitting under a tree simultaneously.  One cannot sit under a fallen tree.|contradiction: An animal is not necessarily a lab dog. If the dog is standing, then it is not sitting. If the dog is on a fallen tree, then it is not under the tree.|contradiction: A dog cannot be standing on a fallen tree trunk and also sitting at the same time. Also, the tree must either be fallen or standing.