BTW, if the bits are assumed to be independent of each other and you're only concerned with eliminating skew, there's a well known simple scheme to eliminate it entirely: group the bits into pairs if the pair is 00 or 11 toss it if the pair is 01 map it to zero if the pair is 10 map it to 1 this method gets you a fourfold reduction in the number of bits in the best case. George