On every level located field, which has 4, 9 or 12 cubes. You can chose several cubes and change green color to red and red color to green. If option "Rectangle" is green in options, white rectangle will be show and you'll see how you can chose this cubes. In some levels you can chose minimum 2, 4, 6 or 8 cubes. Count of minimum cubes indicated before level start
If you still have any questions, you can contact using this e-mail: max(dot)kiev(dot)Ukraine(at)gmail(dot)com
