A plank road is a road composed of wooden planks or puncheon logs. Wood hulls may be made of planks or plywood. The walls are made of vertical wood planks and bamboo and a thatched roof. Most wood is pine with spruce planks on the flat roofs. Houses were constructed with walls of wooden planks, mud, laterite brick, or stone. The logs are then sawn in the same manner as for solid hardwood planks. A typical exterior wooden door might be made out of two layers of oak planks. Construction was of wooden planks, sewn together. The steel base structure is covered with 1292 wooden planks. Leaks between the hull planks of wooden vessels are a particular problem. A set of more complex wooden blocks that includes cubes, planks, and triangular prisms. Competition was conducted on circular or oval race courses with surfaces composed of wooden planks. The flooring was made of pegged planks. The roof was covered with planks and spikes. The runway was and reinforced with pierced steel planks.