Our words and actions often outlive us.  Not unlike DNA, they are the things we leave behind.  We may never know how long or how far they reach.  We may never see the lives they touch.  We may never know how they alter the course of the world.  Often, I think of this as a ball of clay we squeeze between our fingers.  The part we touch and the part that slowly balloons between our fingers both have an impression left on them.  Whether you choose deliberately or it grows delicately beyond your intent, it may harden into cliffs cut away from your receding waves.  We are but lines of sediment in cliffs of everything that came before us.