"In the contruction of houses, choice of woods is made. Straight un-knotted timber of good appearance is used for the revealed pillars, straight timber with small defects is used for the innter pillars. Timber of the finest appearance, even if a little weak, is used for the thresholds, lintels, doors, and sliding doors, and so on. Good strong timber, though it be gnarled and knotted, can always be used discreetly in construction. Timber which is weak or knotted throughout should be used as scaffolding, and later for firewood."
--From Miyamoto Musashi's The Book of Five Rings