FourKnot is a five-piece assembly puzzle. The object is to put the pieces together, such that they form a continuous loop. The solution is a knot shape that has four crossings. According to knot theory, this makes it the second simplest knot. The knot pieces loop like rope with five strands. The pieces are held together by ten 5x5x5-mm magnets. The puzzle is quite confusing. Other than making the knot, one can find various rope shapes.