[From notes based on Oakley Hall. And, yes, I know that the cabbage cannon and Colonel Decker were in completely different episodes.]
One of the reasons "set pieces" are called "set pieces" is because of their ability to set up a series of expectations in the reader's mind and then fulfill those expectations, usually unexpected by some party in the book. To use an example from television: the "A-Team" programs from the 1980's, written by Stephen J. Cannell, usually had a scene with a montage of construction, where the A-Team constructed some improbable device -- say, a howitzer that fires cabbages. Invariably, in the culminating scene, the evil Colonel Decker would come riding up the lone
access road in his Jeep and be swiftly pelted with green, leafy cabbages, to the satisfaction and amusement of the audience. (Of course, in the A-Team, nobody ever got wounded from the automatic weapons which were the team's second resort.)
One of the reasons "set pieces" are called "set pieces" is because of their ability to set up a series of expectations in the reader's mind and then fulfill those expectations, usually unexpected by some party in the book. To use an example from television: the "A-Team" programs from the 1980's, written by Stephen J. Cannell, usually had a scene with a montage of construction, where the A-Team constructed some improbable device -- say, a howitzer that fires cabbages. Invariably, in the culminating scene, the evil Colonel Decker would come riding up the lone
access road in his Jeep and be swiftly pelted with green, leafy cabbages, to the satisfaction and amusement of the audience. (Of course, in the A-Team, nobody ever got wounded from the automatic weapons which were the team's second resort.)