First, for the original problem, there's the trivial solution of (@t1, @t2) because "fairness is not a consideration".

Nice:) Of course, generally speaking random implies unpredictable. The fairness bit was to indicate that not all possible sequences need have the same chance of being produced--but it should at least be possible that every sequence could be produced.

enumerate all binary numbers from zero to 2 ** size of one of the lists

I'm not sure I understand this? If we start with the trivial case of 2 lists of 2 elements. 2**2 = 4; enumerate the binary digits from 0 .. 4 gives:

000
001
010
011
100
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Five numbers; 15 digits; 5 '1's and 10 '0's.

I can't see how that helps to produce the 6 sequences?

P:\test>395791 -N=2
1 2 a b
1 a 2 b
1 a b 2
a 1 2 b
a 1 b 2
a b 1 2
6
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