Yes, you're supposed to assume that every side of each quadrilateral is of length 4. So each is a rhombus (a parallelogram with four equal sides).

Not sure if you wanted a solution, so stop reading now if you want to do the problem on your own, but the angles in each parallelogram must be 60,120,60,120, and if you divide one of the parallelograms along the diagonal, through the 120 degree angles, you'll just be dividing it into two equilateral triangles (because all the angles will be 60). So the diagram is really just six equilateral triangles with sides of length 4.