Jim’s prompt this week is Midnight at the Oasis, a song which conjours up all sorts of visions. For me, the very first thought is of the desert, Egypt, the Sphinx. During lockdown I have responded to this prompt, normally with a song of my own, but this week, let’s do something different.

Firstly, apologies to my UK readers, who might well have seen this one on the quiz show Eggheads a few days ago. In fact it was because I was reminded of this question so recently that I post it today for an international audience.

We’ve all heard of the Riddle of the Sphinx, right? The riddle that says What is it that has one voice, and is four-footed and two-footed and three-footed? And we all know that the answer is a person, because the three stages represent the three stages of life?

But did you know that there was a second, less well-known riddle? This one goes along the lines: There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?

Anybody got any idea what the answer is? Sure, you can look it up, but where’s the fun in that?

If you think you know the answer, post it in a comment and I’ll publish the correct answer, also in a comment, shortly after 6PM my time (GMT + 1), tomorrow.