Brainstring 'R' (Revenge)

The Brainstring 'R' is the second variation on the Brainstring theme (see the Brainstring and the Brainstring Advanced). This version is a sphere with four twistable cuts. The four strings are attached to the eight triangular pieces while the six square pieces are windows through which you can keep track of the state of the strings. Twist and turn the puzzle in all directions to unravel the tightly wound knot. Once the strings are completely separated, the puzzle is solved. Comes in a cardboard box.