Carpe Jugulum (Discworld 23)

' "One for sorrow," said Agnes, watching the bird hop along a branch.

'I always take the view there's prob'ly going to be another one along in a minute,' said Nanny, dropping a stick.

' "Two for joy"?' said Agnes.

'It's "two for mirth".'

'Same thing, I suppose.'

'Dunno about that,' said Nanny. 'I was joyful when our Jason was born, but I can't say I was laughin' at the time. Come on, let's have another look.'

Two more magpies landed on the cottage's antique thatch.

'That's "three for a girl-"' said Agnes nervously.

' "Three for a funeral" is what I learned,' said Nanny. 'But there's lots of magpie rhymes. Look, you take her broomstick and have a look over towards the mountains, and I'll-'

'Wait,' said Agnes.

Perdita was screaming at her to pay attention. She listened.

Threes...

Three spoons. Three knives. Three cups.

The broken cup thrown away.

She stood still, afraid that if she moved or breathed something awful would happen.

The clock had stopped...

'Nanny?'

Nanny Ogg was wise enough to recognize that something was happening and didn't waste time on daft questions.

'Yes?' she said.

'Go in and tell me what time the clock stopped at, will you?'

Nanny nodded and trotted off.

The tension in Agnes's head stretched out thin and made a noise like a plucked string. She was amazed that the whine from it couldn't be heard all round the garden. If she moved, if she tried to force things, it'd snap.

Nanny returned.

'Three o'clock?' said Agnes, before she opened her mouth.

'Just after.'

'How much after?'

'Two or three minutes...'

'Two or three?'

'Three, then.'

The three magpies landed together on another tree and chased one another through the branches, chattering loudly.