Discussion:
I thought the question made it clear that it was ok to draw a box labelled "shift register" and use it, but most students actually drew the circuitry for the insides of the shift register too. This is more work for you, but fine (it represents the same actual circuitry, after all). We tried not to penalize errors in remembering how to draw a shift register, because that wasn't supposed to be required by the question.
There was also apparently some confusion about "0, 1, 1, in that order". I meant that to be in time order, but I guess some students took that as being in recency order (because it did say "the most recent three X samples were ..."), which is opposite, so we accepted either interpretation.
I don't think that either of these issues affected the validity of the question as a test question.