[By analogy with the toyboxes on theatre organs]. Features

added to a program or system to make it more flavourful from

a hacker's point of view, without necessarily adding to its

utility for its primary function. Distinguished from

chrome, which is intended to attract users. "Now that we've

got the basic program working, let's go back and add some

bells and whistles." No one seems to know what distinguishes

a bell from a whistle.