Why I love: Cracking conundrums

They creep inside your brain; subvert your expectations; tantalise and mock you with effortless irreverence. There is much to admire in riddles. Like a good story, you can't sleep until you know the resolution.

Growing up, I found riddles everywhere – questions for which only the most fanciful answers would do: where did my cat really go those long nights on the tiles? (A parallel world under feline rule, perhaps?) Why did my Biology teacher always wear the same dress? (She was an alien, its fabric a layer of her epidermis.)

These mysteries inhabited a curious, occasionally morbid realm where anything was possible. At the very least, they helped to pass the time. One of my favourites? An oldie but a goodie: she who made me doesn't want me; she who bought me doesn't need me; she who needs me doesn't know it. What am I? The answer... a coffin, of course.

The Bloodstone Bird by Inbali Iserles (£5.99, Walker Books) is out tomorrow