in reply to Grep Pattern
You could pre-program your pattern, which imho is elegant and transparent and easily adaptable to more complex situations.
@pat = ( 0, 1, 1, 0 ); $i = 0; @result = grep { $pat[ $i++ % 4 ] } 0..12;
I guess you could also replace "4" with "@pat" to make it even more general.
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