For the area below the window on the front wall, I cut strips of 1/2″-wide balsa wood and stained them dark walnut to match the rest of the trim. (Balsa tends to absorb more stain than the wood used in other parts of the structure, so it ended up looking much darker.) I also installed short strips of wainscot trim where the balsa meets the bricks.
For the bricks, I used the same process as described in my post on the exterior walls: creating each brick individually from polymer clay, gluing them down, and filling the gaps with mortar. The other interior walls will also have some areas of brick, but I need to assemble the structure, lay the flooring, and build the shelving first.
