[2][3] In a strawbale house, a truth window is often used to show the walls are actually made from straw bales.
A small section of a wall is left unplastered on the interior, and a frame is used to create a window which shows only straw, which makes up the inside of the wall.
[4] Many designs exist for truth windows.
Glass may be placed over the window, or an openable wooden panel, or it may be a simple framed opening.
The possible vulnerability of a truth window to moisture intrusion is sometimes raised as a concern.