This triangular box is actually very easy to fold, but Thok has had great difficulties in explaining how to do it.

Vincente Palacios of Spain made a very clear diagram, and on the basis of that Thok has made a new attempt to make a diagram.

First it has to be made clear that the proportion between the paper format for the Lid and that for the Box can both be found on the same silver rectangle, as shown on the drawings to the left.

In the last drawing I have left the helping lines for drawing the crease lines dividing the paper in thirds, and that gives me a great opportunity to tell you about The Thok Trisection Theorem: the TTTT:

"A Diagonal in a rectangle is trisected by a diagonal in the half Rectangle. "

The story about how this came about will be told on the Geometry Cloud, in the near future..

Here on the left is shown the actual proportion between the formats of the Lid and the Box.

It is clearly visible that the triangles on the Lid part are just a fraction larger than those in the Box part.

This gives the Lid a perfect fit on the box, without you having to calculate the sizes of the papers.

This was not calculated I was just trying to use only one sheet of A4.

If you have made the creases sharp and precise valley and mountain folds as indicated, the box will practically fold itself. Have fun.

1) Fold in half and then half the top half. put a crease halving the lower half only at one end of the paper. No scars on the bottom.

2) Form 60 ° by putting the corner to the crease.

3) Copy the 60° making equilateral triangles. Put in creases from the top of the triangles. Mountain fold a diagonal in no. 2 top section from the right.

4) Fold down 2 sections, at the same time mountain fold the diagonal as shown in 5. This will force the paper to become slightly 3D.

5) Swing in left side. Folding left triangle with the arrow on to its neighbor as in 6.

6) Fold the swung part in two and fold it up against the left wall as in 7.

7) Swing in the right section and keep the half triangle at the end up against the wall as in 8.

8) Push the inner lining down starting at the diagonal.

9) No explanation needed here.Lid is complete.

The Box is folded in the same way, but here you don't fold the swinging part in two, just put it up against the side wall, and complete the Box as you did the Lid. It has a perfect fit.

This Box was made in 1993 and dedicated to Elsje van der Ploeg of Holland, the diagram was first made in Jan. 1994.