A more thorough explanation:

A gray mule case is a legal term that refers to a reported case with facts that are almost identical to the current case. The outcome of the reported case can be used to determine the outcome of the current case. This term is also known as the whitehorse case, horse case, goose case, or on all fours.

Suppose a court is hearing a case where a person was injured in a car accident. The facts of the case are similar to a previously reported case where the court had ruled in favor of the injured person. In this situation, the previously reported case is known as the gray mule case, and the court can use its ruling to decide the current case.

Another example could be a case where a person is accused of stealing a car. If there is a previously reported case with similar facts where the accused was found guilty, then that case can be used as a gray mule case to determine the outcome of the current case.

These examples illustrate how a gray mule case can be used to determine the outcome of a current case by referring to a previously reported case with similar facts.