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.
OSB is built by pressing smallers strands of wood together with glue and wax in a hot press. OSB looks a lot like a collage of different wood chips. Unlike itâs plywood counterpart, OSB lacks the forces that tend the wood to warp, and so is easier to get perfect dimensions and avoid warping tendencies.