i once had this "make a PB&J" as part of a written take-home interview.

i knew the schtick -- no matter how precise and complete you are, there is always the possibility for another little gotcha. and that makes it absolute rubbish for a take home because... how much detail do i need to go into to satisfy the manager reviewing this? i think i wrote a couple paragraphs and ended with a little rant about how i know how this problem works and it'd work better in person. i don't know how much they expected somebody to write.