This is a box built out of six two-part panels and twelve connecting units.
Before you panic about making twenty-four parts to construct a simple cube, I would like to point out a couple of things.
First, each unit is extremely simple to fold and second, you can use relatively light-weight papers to make a sturdy container. I made my model with mid-weight wrapping paper (approximately equivalent to 90gsm/24# copier paper) for the outer panels, and 90gsm copier paper for everything else.
To make a 5 cm/2 in cube you will need to begin by cutting twelve squares 10 cm/4 in on a side. If you are using a decorative paper for the outer layer, cut six of those and six of copier paper for the inside layer.
Begin making the panels by folding the top and bottom edges of each square so that they meet in the middle. You don’t have to be precise about where they meet. Just make sure that the edges butt.
Rotate the unit 90º and fold the bottom and top edges to meet. Again, this doesn’t have to be exactly in the middle.
Fold all twelve parts for your panels.
To assemble the outer and inner layers, slip one end of an inner panel into the top of the space in the outer layer.
Rotate the unit 180º, then slide the other end of the inner layer into the second open edge of the outer layer. You will need to gently bend both parts to achieve this. Firmly press flat all four edges of the assembled unit.
The image below shows two assembled panels, one with the inside layer up and the other with the outside layer on top.
To assemble the panels into a box you need to make twelve connectors. Nominally they should be made from 5 cm/2 in squares, but if you are using heavier paper they may need to be slightly smaller. Measure the opening in the side of one of the panels. Using that measurement as the height and width, cut twelve squares.
Fold each square in half once horizontally and once diagonally, opening the paper flat after each fold. Fold all four corners into the middle using the intersection of your first two folds as a guide.
Turn over and re-crease the mountain fold running diagonally across the unit.
To assemble your box, start by attaching the four panels that form the sides. Insert one point of a connector into the opening at the side of a panel, then the other point into the opening on the side of the next panel. Continue doing this until your four side panels are attached. They should form a square tube.
Next insert four connectors in the openings of the top panel. Repeat with the bottom panel and the last four connectors.
Insert the free tip of one of the connectors in the top panel between the layers of one of the panels in the tube, then ease the other three tips into their respective openings and gently push into place. Repeat with the bottom panels.
If you have used a shiny paper for the outer panels, you may find that the connectors want to slide out of place. You can solve this by gluing all the connectors in place except the three showing in the image above. This will give you a box with a lid that opens.
If you would rather not use glue, you can tie everything in place using a couple of lengths of ribbon. Slip the ends of each ribbon between the layers of opposing panels, then tie together at the top.
The advantage of the ribbon method is that the box can be stored flat if you wish to re-use it on another occasion.