DouKaku?

def part(n, mx, a, i)
  if n == 0
    i.times {|j| puts '□'*a[j] }
    puts
  else
    [n, mx].min.downto(1) do |k|
      a[i] = k
      part(n-k, k, a, i+1)
    end
  end
end

def young(n)
  part(n, n, Array.new(n), 0)
end