Another one of Angel Ecija Blanco‘s great designs is the Expandable Square Shaped Origami Coin Purse (original title in Spanish is Monedero). The original design of Angel is the square one. The diagram can be found in the Pajarita Extra Magazine 2008, p. 51.
By looking at the design I figured out that you can apply the basic design of the Expandable Square Origami Coin Purse to actually any n-sided box. So the two other versions (Hexagonal and Octagonal) in this article are based on my own calculations.
A Few Words To This Design
The Expandable Coin Purse is in essence a twist fold box on both ends, that can extend to more height if needed.
Similarities with the Self-Closing Box
By looking at the crease pattern of this design, I can immediately see similarities in regards to the Self-Closing Origami Twist Box. Actually the same V-fold repeats itself in both boxes. In the Self-Closing Origami Twist Box it is hidden underneath the lid. Furthermore, both designs start and end with twist folds. In each one of them one of the twist fold is slightly modified (V-fold) and double layer twist fold.
I folded this design with regular copy paper (my test folds, not pictured), and liked how the paper behaved with the design. Then I folded the actual models with Stardream 120gsm paper. [Stardream paper is metallic shimmery craft paper that feels in weight like copy paper, but slightly stronger.] Stardream paper, in my opinion, is not suitable for this model, as the paper does not withstand the folding and using. If you look closely at my pictures, you will see that the paper disintegrated and the white inner part of the paper shows through. The paper also tore in some places, where you would not expect it to tear that easily.
All in all, this is a medium difficulty origami project that is worthwhile to fold if you happen to have the magazine with the diagram at hand.