Wood Sticks, Planks, or Bats
This includes any type of wood that is broken across the grain. In this case, you want grain that runs wide and flat.
Though actually slightly smaller, their dimensions are listed as 8x16x2. They are made of cement with a small amount of aggregate (additional rock chips and pebbles mixed into the block to strengthen it). Beware of reinforced blocks. They may look similar to regular blocks but they have a stronger aggregate and are much harder to break. These blocks most often come in gray and red and may be flat on both sides or the bottom may have small ridges. The color makes no difference but ridges may make it very slightly stronger. These blocks have a consistent hardness. Wet blocks are harder to break so insure blocks that have been stored outside are dry. One block equals about five strong boards and is cheaper than one board.