Lol! I think JMac meant to say Radical Symmetric cores. However, that information is false. I have seen it in other balls (the Voodoo Layout was floating around). And I have done the "MO"tion hole in a Rotogrip Shatter, with success I might add. I will say that maybe the effects of the "MO"tion hole are magnified more so in a Radical Symmetric than any other symmetric.
Kudos to Phil and Mo for designing, testing and making this process somewhat generic. I had heard that a years worth of testing went into this and it is an astonishing achievement.