Question 12
Criminals build 16 walls between Superbeaver and the city, as shown. Superbeaver can see through exactly one wall. What is the minimum number of walls to destroy so that Superbeaver can stand by the river and look into the city?
Editorial convention for the conditional answer: require visibility across the entire pictured city frontage, along the vertical sightlines drawn, with at most one retained wall on every sightline. The original wording does not explicitly say “entire frontage”; this stronger interpretation is needed for the listed choices.
Editorial convention for the conditional answer: require visibility across the entire pictured city frontage, along the vertical sightlines drawn, with at most one retained wall on every sightline. The original wording does not explicitly say “entire frontage”; this stronger interpretation is needed for the listed choices.