i think height is also one factor in classifying players, although not that big of a factor i think. sure there are 6'6" center, but no way you can find a 5'9" center or a 7'2" pg
http://statistik.basketball-bundesliga.de/bbl/stats/player/index.php?team=418&saison=2007&spieler_id=2752
He plays sometimes as Center, and is a Pofer Forward who plays mostly in pain ... His height is more 1.84 = 6 feet, then the 1.88cm who stand on the stats. It is pretty cool to look at him, because he is a great player and how he get all his board is impressive - so he earned his nickname Mr incrdible.