def find_max_min(numbers)
  if not numbers
    return [None, None]
  end
  max_num = numbers[0]
  min_num = numbers[0]
  for num in numbers[1...-1]
    if num > max_num
      max_num = num
    end
    if num < min_num
      min_num = num
    end
  end
  return [max_num, min_num]
end
def reverse_list(items)
  reversed_items = []
  for i in (items.length - 1...- 1).step(- 1)
    reversed_items.append(items[i])
  end
  return reversed_items
end
numbers = [3, 1, 4, 1, 5, 9, 2, 6]
max_val, min_val = find_max_min(numbers)
print("List: #{numbers}", "\n")
print("Max: #{max_val}, Min: #{min_val}", "\n")
print("Reversed: #{reverse_list(numbers)}", "\n")
print("Original list unchanged: #{numbers}", "\n")