Graham Carter - the voice of age and experience

Question: when is a triangle not a triangle? Answer: when it’s on Facebook.

I really must stop looking at what people say on there - because I get embarrassed for grown-ups when they say really dumb things.

At least I have now cured myself of clicking on links to find out what people are saying about things in the news, realising that time is too precious to waste a second of it on the ignorant, bigoted and heartless vitriol that is rife there.

But last week I was accidentally lured into what looked like a harmless puzzle, posted by some restaurant or other, and shared by a friend, which had gone viral.

To be in with a chance of winning a £30 voucher, you had to work out how many triangles were in a shape somebody had drawn, and then share it with your friends.

It is one of those puzzles (like a wordsearch, jigsaw or Where’s Wally?) where the answer is there all the time, and whether you get it or not usually depends on only one thing: whether you can be bothered to devote enough time to working it out.

I had a kettle boiling, so I sat down and came to the answer 18, although I have to admit I resorted to drawing shapes on the back of an envelope because it was too tricky for my little brain to do in my head.

Then I made a big mistake. I checked other people’s comments.

I only wanted to see if I had the right answer.

I did, in fact, but about half didn’t, probably because they hadn’t spent enough time on it, and they were therefore a bit wrong.

But others were very wrong.

And that’s an understatement.

Some people - and there were several of them - came up with an answer of one, gleefully informing fellow puzzlers that triangles must have three equal sides. A few others said no - you’re wrong - only two sides have to be the same.

It was at this stage that I started to think back to the first things I learnt at school, and I came to the conclusion that our infant school teacher probably told us what a triangle was on Day One, and when I went to school you only had to remember one thing about them: if it has three sides, it’s a triangle.

I can only assume that those who hadn’t grasped triangle basics hadn’t turned up on Day One, but even then, I ask you: how can anyone go through life not knowing what a triangle is?

But that’s not the half of it.

More shocking than the ignorant are those who simply aren’t embarrassed to be ignorant.

And hold on, because we are only just coming to the most disturbing aspect of all this.

Being wrong is forgivable, of course, and even being the last one in the room to realise it is fair enough, but what we now have are people who - despite seeing others coming to such a consensus about basic things that they must surely be right - still don’t even consider that they, themselves, could be mistaken.

They have made their own minds up about what constitutes a triangle, and nobody is going to tell them otherwise.

And even if they conceded their ignorance, no doubt some of them would tell you they have a goddamn right to their ‘opinion’ about triangles.

So my question to you is this: were they there all along and has social media merely revealed their existence to us, or has it created them?

A square of Toblerone to the first person to come up with the answer.