Flat sawn wood (especially oak) will often display a prominent wavy grain (sometimes called a cathedral-window pattern) caused by the saw cutting at a tangent to a growth ring; since in quartersawn wood the saw cuts across the growth rings, the visible grain is much straighter; it is this evenness of the grain that gives quartersawn wood its greater stability.
Flat sawn wood (especially oak) often exhibits a prominent wavy grain (sometimes called a cathedral-window pattern), caused by the saw cutting at an angle to a growth ring; since in quartersawn wood, the saw cuts across the growth rings, the visible grain is much straighter; it is this evenness of the grain that gives quartersawn wood its greater stability.