Question: how many cubes are needed to build a tower like this but 12 cubes high?
Answer: They saw a center column 12 cubes tall and 4 identical “legs,” each consisting of 1 + 2 + 3 + … + 9 + 10 + 11 = 66 cubes. Ultimately, these students calculated that a Skeleton Tower with height 12 units would require 12 + 4 ´ 66 = 276 cubes.