A white dog is watching a black dog jump on a lawn next to a pile of large rocks .
It is impossible that a white dog watches a black dog jump over an obstacle on an obstacle course .
Chances are about even that a white dog watches a black dog jump over an obstacle on an obstacle course .
It is impossible that a white dog watches a black dog jump over an obstacle on an obstacle course .
A white dog watches a black dog jump over an obstacle on an obstacle course .