Some time ago, Peter, Megan and I were trying to come up with a limerick for the British Association's Universe poetry competition. The deadline has long since passed by and we never came up with anything that was good. We did write four lines of a limerick about Einstein but couldn't think of a last one. So, just for fun, I thought I would see if anyone out there can finish it.
While pond'ring the nature of light
A German had sudden insight
For Einstein declared
That E's m c squared