Non-Modular Diamonds: 6

These non-modular diamond-shaped boxes are fairly easy to make and reasonably sturdy, even when made with softer or thinner origami paper. When made with scrapbook paper or other thicker paper, they are very sturdy.
 
Tomoko Fuse, the designer of these boxes, recommends A4 (297 mm x 210 mm) paper; however, other sizes of rectangular sheets may be used to create boxes of various dimensions. The height of the box may be adjusted by changing the position of a single fold early in the folding steps.