Well, after several hours stumped, I decided to post to you all in desperation...and what do you know, two seconds later I solved my own problem. I simply forgot the parentheses after "show" on the blank canvas.
Great! Thank you. I would imagine it's based on if-elif-else statements, but I can't figure out how to structure the questions in the block loop such that the control flow does what I want it to. Cheers.