Insulation with embedded structure

Most of the picture is taken up by a wall, its far end near the left of the picture, which is entirely covered in sheets of a soft matt brown material, except where three pieces of wood about 10 centimetres broad have been let into it at different levels - higher at the back, lower in the middle, and a little higher at the closest end near the bottom right of the picture. There is a narrow gap visible between the bottom of the brown material and the tiled floor.