A closeup of OSB sheeting. According to its Wikipedia entry, "Oriented strand board, also known as OSB, waferboard, Sterling board or Exterior board (UK) and SmartPly (UK & Ireland), is an engineered wood product formed by layering strands (flakes) of wood in specific orientations... The finished product has similar properties to plywood, but is uniform and cheaper. When tested to failure, OSB has a greater load bearing capacity than milled wood panels. It has replaced plywood in many environments, especially the North American structural panel market. The most common uses are as sheathing in walls, floors, and roofs."
