 "Portal" is Valve's spiritual successor to the freeware game "Narbacular Drop", the 2005 independent game released by students of the DigiPen Institute of Technology; the original "Narbacular Drop" team was subsequently hired by Valve.Valve became interested in "Narbacular Drop" after seeing the game at DigiPen's annual career fair; Robin Walker, one of Valve's developers, saw the game at the fair and later contacted the team providing them with advice and offering to show their game at Valve's offices.After their presentation, Valve's president Gabe Newell quickly offered the entire team jobs at Valve to develop the game further.