Programming challenge: wildcard exclusion in cartesian products

[wkehowski at cox.net]

Here is an nice intro to K:

http://www.kuro5hin.org/?op=displaystory;sid=2002/11/14/22741/791

  "This is where K starts to set itself from apart from most of the
common programming languages in use today. You rarely write loops in K
(KDB is 100% loop-free), instead you use adverbs. An adverb modifies a
function, returning another function, changing the ways it operates
over its arguments and what it does with it's return values."

How about an interactive loop-like version? Generating the target set
is good for baby test cases but not if the cardinality of the target is
large. Does that make the problem more intersesting?