1. Create a new worksheet by clicking File Menu => New => create an A4 size worksheet, then click OK
  2. Make 1 rectangle with Width = 21 cm and Height = 29.7 cm or equal to the size of the width of our work that is A4, and place it exactly in the middle of the art board
  3. Now we will add a rectangle with a distance of 1 cm inside of the rectangle we first made. Click Object Menu => Path => Offset Path … => then an option for Offset Path => fill the Offset with the number -1 cm, because to add to it means minus.
  4. After that, make a horizontal line then copy down, and press CTRL + C and CTRL + V to repeat copying and pasting the line automatically.
  5. The line group that you have made earlier, then rotate as many as 45 Degrees, and place each other cut on the frame that we made earlier
  6. Selection of all objects and lines with the Selection Tool, also can press CTRL + A (Select All)
  7. Open the Window Menu => Pathfinder => select Divide
  8. Then Select Menu Object => Ungroup
  9. Select the object that is inside and press delete on the keyboard.
  10. After that, give the color as desired