The next two installments in the seven-part video series showing Valve's Portal 2 presentation from E3 2010 are now available. In part four, we are introduced to the "Thermal Discouragement Beam," which de-incentivizes anything in its path with heat, and lots of it. Part five shows off the "Pneumatic Diversity Vent," which allows players to dispose of things that blow using a thing that sucks (and in a nice touch, there are no bags to empty). Both clips are embedded below.