[michaelchisari]

it is not difficult for you in your cover letter to indicate that I might be interested in x,y,z in project foo because they demonstrate a,b,c, and I can find the code on github.

I think it's fair to assume that after my years in the industry, that I would not simply hand you a link with no context, nor that I would be applying for a job which didn't relate to the work I had done, and I don't feel these arguments apply to the situation I presented.

But as far as I'm concerned, my preference would be to hire based on established code and real world tasks, not abstract puzzles. Not only are puzzles like these faddish, I've met too many programmers who excelled at puzzles, but were severely lacking in more mundane (but all too necessary) departments, so in terms of what kind of things I would use to weed people out, I'd do a set of real world tasks like the one I mentioned above, well before I'd ever give a list of clever puzzles to solve.

Assuming the applicant didn't contribute to open source, which would always be a huge plus in my book.