From the publisher's website: This is the expansion set to Quintillions. It contains an additional 18 non-flat 5-cube pieces ("pentacubes"). With this expansion you can make even more puzzles and larger game versions become possible. Booklet includes puzzles and games that combine just the 18 expansion pieces and all 30 pieces total. There is an optional case that stores the pieces from both Quintillions and Super Quintillions in one carry case available from Kadon Enterprises for $50 USD. Expands: Quintillions