programming The opposite of top-down design. It is now

received wisdom in most programming cultures that it is best

to design from higher levels of abstraction down to lower,

specifying sequences of action in increasing detail until you

get to actual code. Hackers often find (especially in

exploratory designs that cannot be closely specified in

advance) that it works best to *build* things in the opposite

order, by writing and testing a clean set of primitive

operations and then knitting them together.