'Why would the bagpipes be dressed in pyjamas?' asked ibb.

'They weren't,' I replied, 'it was the tartan. That's just what the octopus thought they were.'

'I see,' said obb, not seeing at all. 'Would you mind going over it again?'

'That's it,' I said resolutely, 'you're going to have a personality if it kills me.'

'Kill you?' enquired ibb in all seriousness. 'Why would it kill you?'

I thought carefully. There had to be somewhere to begin. I clicked my fingers.

'Sarcasm,' I said. 'We'll start with that.'

They both looked at me blankly.

'Well,' I began, 'sarcasm is closely related to irony and implies a twofold view – a literal meaning yet a wholly different intention from what is said. For instance, if you were lying to me about who ate all the anchovies I left in the cupboard, and you had eaten them, you might say: "It wasn't me" and I would say: "Sure it wasn't," meaning I'm sure it was but in an ironic or sarcastic manner.'

'What's an anchovy?' asked ibb.

'A small and very salty fish.'

'I see,' replied ibb. 'Does sarcasm work with other things or is it only fish?'

'No, the stolen anchovies was only by way of an example. Now you try.'

'An anchovy?'

'No, you try some sarcasm.'

They continued to look at me blankly. I sighed.

'Like trying to nail jelly to the wall,' I muttered under my breath.

'Plock,' said Pickwick in her sleep as she gently keeled over. 'Plocketty-plock.'

'Sarcasm is better explained through humour,' put in Gran, who had been watching my efforts with interest. 'You know that Pickwick isn't too clever?'

Pickwick stirred in her sleep where she had fallen, resting on her head with her claws in the air.

'Yes, we know that,' replied ibb and obb, who were nothing if not observant.

'Well, if I were to say that it is easier to get yeast to perform tricks than Pickwick, I'm using mild sarcasm to make a joke.'

'Yeast?' queried ibb. 'But yeast has no intelligence.'

'Exactly,' replied Gran. 'So I am making a sarcastic observation that Pickwick has less brain power than yeast. You try.'

The Generic thought long and hard.

'So,' said ibb slowly, 'how about … Pickwick is so clever she sits on the TV and stares at the sofa?'

'It's a start,' said Gran.

'And,' added ibb, gaining confidence by the second, 'if Pickwick went on Mastermind, she'd do best to choose "Dodo eggs" as her specialist subject.'

obb was getting the hang of it, too.

'If a thought crossed her mind it would be the shortest journey on record—'

'Pickwick would cause a sensation at Oxford – but only from within a specimen jar—'

'All right, that's enough sarcasm,' I said quickly. 'I know Pickwick won't win "Brain of BookWorld" but she's a loyal companion.'

I looked across at Pickwick, who slid off the sofa and landed with a thump on the floor. She woke up and started plocking loudly at the sofa, coffee table, rug – in fact, anything close by – before calming down, climbing on top of her egg and falling asleep again.