Despite a number of theories in circuit analysis, little is known about the behaviour of ideal equal voltage sources in parallel, connected across a resistive load. We neither have any theory that can predict the voltage source that provides the load current, nor is there any method to test it experimentally. In a series of experiments performed on 100 students, it was found that this circuit is often misunderstood on symmetry grounds. This paper addresses this issue by showing how different circuit analysis methods fail to provide an answer.