The cube unravels, staying in 1 piece like a snake. Can you get it back to the cube? A Great puzzle that stays in one piece so there are no pieces to lose. Good initial solution time is about 1 hour, but with practice this can be done very fast (under 10 secs) and made to look deceptively easy - thus has a high "showoff" factor:) These premium models have beveled edges on each of the 27 cubes that make up the snake. This gives an attractive and comfortable feel in the hand. Size small is about 1.8", size med 2.4", size large 3"