Brain String Original - Brain teaser by RECENTtoys

Brainstring Original is a patented brilliant new puzzle game for people between 7 and 70. Brainstring Original comprises a transparent polycarbonate cube with 12 elastic strings. Using an ingenious pattern of incisions the strings can be moved through the cube. The result: complex knots appear on the inside. The main goal of the game is to switch the outside button colors, without creating a knot inside. It seems impossible but...