gistfile1.rb

# Invoke as follow
# $ ruby build.rb x
# Where $ is your bash prompt and x is the glass ceiling you want to build.

def build(n)
  unless (n-1) < 0
    build(n-1)
  end
  unless (n-2) < 0
    destroy(n-2)
  end
  puts "Build #{n}"
  unless (n-2) < 0
    build(n-2)
  end
end

def destroy(n)
  unless (n-2) < 0
    destroy(n-2)
  end
  puts "Destroy #{n}"
  unless (n-2) < 0
    build(n-2)
  end
  unless (n-1) < 0
    destroy(n-1)
  end
end

def main(args)
  build(args[0].to_i)
end

main(ARGV)