Hardwood plywood is an engineered wood composed of cross-grained thinly sliced wood veneers.  Cross-graining is the practice of orienting the wood grain of each plywood layer at right angles to the one below it. This alternating criss-cross pattern is behind plywood's impeccable strength and rigidity. There are a few key reasons why cross-graining is so integral to plywood's overall strength:  It helps to distribute weight more evenly across the surface of the material. This is because each layer is supporting the one above it, rather than all the weight being concentrated in one area.Cross-graining makes plywood less likely to warp or deform over time. When all the grain is going in the same direction, it is easier for the plywood to bow or twist out of shape. But when the grain is alternating, it prevents warping, making it much more difficult for the plywood to deform.Cross-graining gives plywood added strength in both tension and compression. This means that it can withstand more force without breaking or sagging.