[DanDon]

Having just bought empty cells and super cells at the local Wal*mart, this turns out to be a not so small issue, not only for people affected by colorblindness, but also for people with perfect vision. Being able to tell if you're carrying more than one empty cell during the heat of the moment, as opposed to one empty cell and one moon rock will be extremely difficult under tournament conditions (i.e. lighting, glare, robot traffic, etc.).