premise: A man hanging by a cable from the tower. hypothesis: A man is playing a piano in the street.
contradiction: Hanging implies that one is holding onto an object (i.e., a cable) with one's extremities and dangling in open air beneath that object. It is unlikely that one would be able to be hanging and playing a piano simultaneously. Also, "in the street" implies that one is on ground-level, whereas a cable from a tower would presumably be at a higher elevation.