Masu Box

This is a traditional design for a square box. The height of the sides can vary from almost flat to the same as the width of the base, making a cube-shaped box. A matching lid can be made for any shape box by making the base slightly larger and the sides slightly shorter.

Folding Instructions

1. Crease a square sheet of paper along the horizontal and vertical center lines.
   
2. Turn over and fold all four corners to the center.
   
3. Fold one edge inward to meet the center line.
   
4. Unfold step 3 leaving a crease, and crease the remaining edges the same way.
   
5. Unfold one corner and fold its adjacent sides up 90°.
   
6. Fold the entire corner up, collapsing the two triangles flat against it.
   
7. Continue folding the corner toward the center, and flatten it into the bottom of the box. Repeat from step 5 on the opposite corner.
   
8. Press the second corner into the base to complete the box.
   

Size Variations

The position of the fold in step 3 determines the final box's width and height. Placing the crease halfway between the edge and center line as above creates a box with 2:1 aspect sides. Moving the crease outward makes the box larger and flatter, while moving it closer to the center makes it taller with a smaller base.

Shallow Lid

1. To make a lid for another box, start with a sheet of paper the same size or smaller. After step 2, place the first box directly centered over the new one.
   
2. Fold the sides up using the first box as a guide and continue folding the second box normally.
   
3. A lid made this way will fit over the first box.
   

Square Sides

1. To make a cube-shaped box with square sides, fold the edges along a line one third of the way between the outer edges.
   
2. When folding step 6, the two triangles will overlap each other.
   
3. Continue folding the box.
   

-- StephenCavilia - 2009-08-26