‘The Thing told me,’ said Masklin. ‘It’s something called critical path analysis. It means there’s always something you should have done first. For example, if you want to build a house you need to know how to make bricks, and before you can make bricks you need to know what kind of clay to use. And so on.’
‘What's clay?’
‘Don’t know.’
‘What’re bricks?’
‘Not sure.’
‘Well, what’s a house?’ she demanded.
‘Haven’t quite worked it out,’ said Masklin. ‘But anyway, it's all very important.’ (Truck)