casting the runes

One of ICL's most talented systems designers used to be called out occasionally to service machines which the field circus had given up on. Since he knew the design inside out, he could often find faults simply by listening to a quick outline of the symptoms. He used to play on this by going to some site where the field circus had just spent the last two weeks solid trying to find a fault, and spreading a diagram of the system out on a table top.

He'd then shake some chicken bones and cast them over the diagram, peer at the bones intently for a minute, and then tell them that a certain module needed replacing. The system would start working again immediately upon the replacement.

– The Jargon File, v4.4.7