Build A Cardboard Box

Step 2 Mark the Corners

Now there is one long piece of cardboard laid on the floor. Place the item(in this case- a framed picture) on the cardboard where half the width of the item is equal to the space between the item and the edge of the cardboard. (So if you were to fold the cardboard up on the item, it would only be halfway across that side.) From top to bottom, cut very lightly with the box cutter to draw a cut line into the cardboard at the place the item's edge meets the cardboard.

Do not cut away the cardboard to remove it at this line! Just make a mark with the blade that cuts the top surface of the cardboard! (Later we will see that this makes the cardboard fold perfectly.) Make another parallel cut line on the other side of the item. Then roll the item on its side so one side is still on the previous cut line, and make another parallel cut line while the item is at 90degrees in the air. Lay the item down to finish its 180degree roll, keep one side on the previous cut line, and make another parallel cut line on the edge that just touched down on the cardboard.

Now leave half the width of the item as space on the cardboard(like we did in the first cut line) and cut this remaining excess cardboard off completely, from top to bottom using the box cutter.