A sparse ruler is called optimal if it is both minimal and maximal. Since the number of distinct pairs of marks is m ( m â 1 ) / 2 {\displaystyle m(m-1)/2} , this is an upper bound on the length L {\displaystyle L} of any maximal sparse ruler with m {\displaystyle m} marks.
1 One 23/32-inch 4x8-foot plywood piece weighs approximately 67 pounds, while a piece of OSB of the same dimensions weighs approximately 78 pounds.
Building codes consider OSB (Oriented Strand Board) and plywood interchangeable and refer to both as âstructural wood panelsâ as both OSB and plywood panels are created when wood is glued and compressed to form a rigid panel.Despite the obvious similarities, there are some essential differences.hen OSB panels are created, thin wood strands are combined with adhesive and then hot-pressed into sheets. OSBâs strength comes from the fact that strands of wood are aligned in each layer and that each layer is perpendicular to the one below (they mimic plywood in this perpendicular layering).