Most species of wood used in hardwood flooring have some special feature that is only visible when the lumber is radially cut, a milling process more commonly known as "quarter-sawn." Every species will showcase tight, vertical grain. Maple figuring can result in "flaming" or a "tiger-stripe" pattern perpendicular to the grain structure; walnut will normalize in color almost completely and present burling and flame. Quarter-sawn oak boasts organic, cross-grain patterns of figuring and flecking that have remarkable depth. The vertical grain structure is still clearly visible, but this historic, old-growth oak houses an explosion of fleck.