Here's a lovely way to present your favourite pictures of your family in your christmas tree or wherever you want to show them off. Don't cut an inch of your printed photographs and have a magnificent volumetric display. Fancy, easy and cheap to make!

My sister had a moment of inspiration while we were discussing the failure of the use of tetrahedral packages by a milk company. While it's quite a tricky thing to pile up in your fridge, it's really easy to build, since you only need a regular sheet of paper (any rectangular surface of any relative size is fine) to build it. This easiness comes from the fact that it's not just a tetrahedron, but an isosceles tetrahedron, which makes the folding so much simple.

Step 1: Tools and Materials

Tools:

Scissors
Sewing machine or needle

Materials:

Thread
Printed picture (average paper is fine, but glossy paper is way better)
Ribbon

The total cost goes around 0,11€ per ornament if you buy a bunch of pictures instead of printing them by separate or with your printer. It can always be cheaper if you find a good printing offer, make them with cheaper paper or use wire instead of ribbon.

Step 2: Folding

The basic idea is to use the whole surface of the picture, instead of cutting it to fit the usual way of constructing an isosceles tetrahedron.

An isosceles tetrahedron is, by definition, a polyhedron of four sides which are congruent, thus, equal in size. Instead of building it the usual way by drawing four equal isosceles triangles one after the other, the fourth side will be made using the two right triangles formed by folding in each side of the picture.

The difference then is that instead of joining the figure by the edges of the last two sides, the last side is made by joining the edges of the two formed right triangles.

Step 3: First Seam

Bend gently the picture in half along the longer edges but do not press or mark the bending, we only want to get the upper sides lined up.

Put the ribbon between both sides and sew the upper edge.

Step 4: Second Seam

Line up the short edges of the picture and sew them together, making an L-shape with the first seam.

Step 5: Third Seam

Take the base of the picture and bend it perpendicular to both the first and second seam, giving it the final form of the figure. Try to shape well the rest of the edges. They should come out naturally as you bend the base, but a bit of help to make them sharper and avoid irregularities is advised.

Now, sew those last edges as in the previous steps.