The Furrowed Brow (A riddle)

The bright white surface sits abroad and gleaming All of its edges sharp and crystal clear The white face stares ablank and motionless Not a single emotion shows upon him But soon his mood will change and wrinkles form Upon his furrowed brow his wisdom shows People come and go to learn his knowledge They gaze minute upon minute becomes hours Hour upon hour turns to days of gazing But soon his wisdom fades with one broad stroke The place to which it goes nobody knows... Maybe it sits upon the palm of him Inside that little cube that dwells on there The white abyss sits clear empty and void Again his brow dost furrow deeply down More knowledge is revealed upon his face The wrinkles grow and wisdom shows, they stare The face returns a glare his wisdom leaving Stroke by stroke the wrinkles leave and... The wisdom fades, fades fades into the white abyss