The Hollow Series presents an intriguing, innovative advance in twisty puzzles. The no-core puzzles’ movements are unlike anything experienced by even the most experienced puzzle-solver. With a combination of inventive gameplay and stunning design, Meffert Hollow series are one part gift, one part puzzle, one part treasure!
Twist and turn to scramble the colors.  Then try to make one solid color per face. 
Ages: 14+
Inventor: Oskar van Deventer

• See at Puzzle Master