Wooden wall

A wall made of wood, enclosing a closed area to form an indoor space (length or width, with one side not exceeding 20), keeping warmth. It blocks some land-based monsters, but a few monsters may gnaw at the wooden walls. When all four walls are enclosed, it forms an indoor space, which is warmer and beneficial for indoor activities If there are no walls within 10 squares up, down, left, or right from any grid in the closed space, it is considered not indoors.