All engineers should keep in mind the story of the small boy who went into a shop and asked for a package of detergent. 'What do you want it for?' asked the proprietor. 'To wash my budgerigar in', said the boy. 'That won't do it much good', replied the man.

Next day the boy came back. 'How is the budgerigar?' said the proprietor. 'Dead', said the boy. 'I warned you', said the man. 'It was not the detergent that did it', replied the boy, 'it was the wringer.'

Designers, too, often fail to recognize where the real danger may lie....

-- Gordon L. Glegg, _The Design of Design_