You will no doubt think that you have seen many crafts like this before. However usually in this kind of 3-D figure, you are told to glue along the back fold to hold the pieces together. What's new here is the way the different parts are held together, so that you need no glue, and once assembled, the whole piece is very stable and will not fall apart , and in the end you can undo it for safe stowing away till you need it again.
Of course you can think up different forms and shapes, but I am using the "Christmas Tree Model" because I actually made a number of them.
You
will need three pieces cut as in the figure in the shape desired (Christmas
tree) as well as two disks.
Please note that the template above is 10cmX10cm. If you double that size, that is, 20cmX20cm, you will get a very good result
Cut along the outside lines as well as slit the two small horizontal interior lines. For the disks too, cut out two pieces and slit along the six internal lines.
Next, fold each tree unit into two along the middle vertical line. Now fit the disk's slits into the tree's slits, OA and OB in the disk into OA and OB in the tree, and the second disk goes into OA' and OB'. Once assembled, the tree cannot fall apart on its own, because of the way the slits are, i.e. at an angle to each other.
