Plywood has an odd no. of layers so that this is at right angles for strength inside but runs the same way outside
Some applications require plywood sheets that have a thin layer of 
plastic,... [DOC] [TLE] Plywood - Expand Your Mind - Topics [PAR] There is usually an odd number of plies, so that the sheet is balancedthis ... 
Because plywood is bonded with grains running against one another and with an 
odd ... below and right) may only have their plies (layers) arranged at right angles 
to ..... suitable for outdoor use, but because moisture affects the strength of wood,
... [DOC] [TLE] Chapter 6: Aircraft Wood and Structural Repair - Federal Aviation ... [PAR] 7,700 airplanes made of spruce, birch plywood, and balsa ... were produced with 
wood spars and wings, but today only a ... of deterioration, and a detailed internal 
inspection has to be .... or lines running across the grain.