Marshall, Ted, Barney, and Robin are in the Robin house. Suddenly the light goes out and one of the boys kisses the Robin
Robin asked who kissed me and the three men replied as:
> Marshall says Ted did it
> Ted says Marshall is lying
> Barney says he did not.
Just one of them is telling the truth. Who kissed the girl?
Barney kissed Robin and Ted is telling the truth.
> Marshall says Ted did it
If this is true, then the last statement must be true as well.
> Ted says Marshall is lying
Must be the only statement true.
> Barney says he did not.
If this is true, then one of the first two statements must be true as well.