The boomerang. A simple enough concept, you might think, although perhaps not so simple if you've ever flung one skywards and expected it to come back to you.
But that's the real thing. It was the boomerang as metaphor that TES covered in these pages a couple of months back ("Now I am the master", Feature, 24 October). It's a straightforward scenario: sent out into the world after your studies, you end up gravitating towards your old school as a teacher.
I found myself reading the article with a growing sense of recognition. In my case, the boomerang experience was also the very first class I ever taught. It's a real challenge when you have to stand up in front of a group of strangers and convince yourself - before you can even attempt to convince them - that you are a fit and proper person to play the role of teacher. It doesn't help when this is taking place in the very same room where you began your career at "big school" as a quivering 11-year-old.
I arrived uncharacteristically early for my ordeal. Not a lot had changed: the bare walls, the shabby desks with their antique carvings, the roll-around blackboard. It was an A-level literature class and I had prepared two war poems for the students to discuss. For some reason, I had convinced myself that they would all just sit there and refuse to say a word.
The first student arrived. She was at least 20 years older than me. "Hello," I said. "I'm your teacher."
She gave me look that said "Who do you think you're kidding, sonny boy?", before replying: "And I'm your first student."
There was worse to come. The second person through the door had a familiar look about her.
"Good evening, Stephen," she said. "It's been a long time, hasn't it?"
I groped around for a name: Gillian. With a growing sense of panic, I recalled that Gillian and I had briefly been an item, about 10 years earlier.
"So.so.you never did take your A-levels then," I stammered.
"No. As you may remember, I fell pregnant instead."
It occurred to me that I could just run out the door. But hang on, I told myself, you are a professional. And anyway, nothing like that ever happened between me and Gillian. It must have been that older man - the one who had actually started shaving - that she dumped me for.
"How nice," I said at last. "You've got a child, then."
"Two, actually. And now I'm back to finish my education. How funny that you're going to be my teacher."
When the class finally started, I tried my hardest to focus on Rudyard Kipling and Wilfred Owen. But I couldn't help wondering if Gillian was telling her fellow students her marks out of 10 for my youthful attempts at courtship. As they left the room at the end of the class, Gillian paused at my desk.
"Do you remember our last evening together?" she asked.
"I can't say that I do," I replied, primly tidying my papers.
"You had too much to drink and were sick all over the carpet. My mother still hasn't got over it, even now."
Stephen Jones is a lecturer at a further education college in London