First, read the English article below.

With the red side still down, take the lower right corner and bring it to meet the upper left corner. Crease the fold with your finger. Open it up to reveal a new diagonal crease. Rotate the paper 90 degrees and repeat the previous two steps. Open it up to reveal two diagonal creases that form an "X" through the paper. In each corner of your paper, you should now see a small square that is divided by a single diagonal crease. Take hold of the top left corner and fold it inward, creating a crease that is perpendicular to the original diagonal crease. The corner of your paper should align with the bottom-right corner of the small square. You should now see a small "X" in the top left corner. Draw a line along the new crease. Take the bottom-right corner and bring it up so that the point of the corner just touches the new line you drew in the previous step. This should create a new crease that runs parallel to one of the lines making up the big "X," specifically the one running from bottom-left to top-right. Unfold and draw a line along the new diagonal crease. Turn the paper 180 degrees and repeat the previous four steps. You should now see three lines running parallel from the bottom-left corner of your paper up to the top right. Now turn the paper 90 degrees and repeat steps 5 through 9 (of Part 2). When you are done, you should have three parallel lines running from bottom-left to top-right and three running from top-left to bottom-right. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Gấp đôi tờ giấy theo đường chéo. Mở lại tờ giấy. Gấp đôi tờ giấy theo đường chéo ngược lại. Mở giấy ra lại. Gấp góc trên bên trái. Mở lại tờ giấy và đánh dấu mọi nếp gấp mới được tạo ra. Gấp góc dưới bên phải lên đường mới. Mở lại tờ giấy và đánh dấu. Xoay giấy và lặp lại. Xoay và lặp lại.