"The infernal workshop"

‘A crime,’ he said slowly, ‘is like any other work of art. Don’t look surprised; crimes are by no means the only works of art that come from the infernal workshop. But every work of art, divine or diabolic, has one indispensable mark – I mean, that the centre of it is simple, however much the fulfilment may be complicated...'

~G.K. Chesterton: The Innocence of Father Brown, III. The Queer Feet.