Kiwi Drive was their robot name...
The idea isn't brand new. If you want to do web research, the drive is called the Killough Omnidirectional (holonomic) drive system. However, this system isn't really feasible without 3 matching motors, or your wheels will have different torques and speeds. It's a pretty ingenious design though. You may think "Omniwheels? That kills your pushing power." However, if you look at it no matter what direction you push against the bot, you are pushing directly against 2 omniwheels.
4 Wheel holonomic drive
This one wouldn't require 4 identical motors. Just as long as you use 2 identical motors in one direction and 2 in the other direction.