No.
Are there undetectable walls in outer space? Possibly. We can't detect them.
If it is a concentric castle, then it would have a set of outer walls and inner walls. Basically, the name is outer walls, if you were asking for the proper terminology. If you're inquiring towards their use, outer walls are thinner than inner walls and their purpose is to provide a space between the inner and outer walls from which attackers may be stopped before reaching the castle.
Bailey is defined as the outer walls that surround a fortification and it can also be used to refer to the space between or outside these walls.
The Indus people probably wanted privacy or they used the outer walls forsomething else,maybe they put decor on the outer walls
mushroom
Baseboard electric heaters are placed on the outer walls of a room in order to radiate heat towards the center of the room. They also heat up the outer walls of which usually are cooler than the inner walls.
If These Walls Could Talk - The Outer Limits - was created on 1995-07-30.
it had 2 walls the inner wall and the outer wall.
The His-Purkinje system is the part of the heart's electrical system that follows the outer walls of the ventricle.
cells
Guard cell walls do not have a uniform thickness. The inner walls are thicker than the outer walls.
follow the outer walls.
so the walls can be more beautiful as the people usually will see it