Around August 2020, I consulted Ivan for active origami designer forum, hoping I can learn something there. He pointed me to Origami-Dan Discord server which is what I exactly needed. Later, he asked me if I wanted to join him designing bird of paradise. It sounds like a good learning experience, so I agreed. Each of us will come up with our own design and fold.

Bird of paradise is a family of bird in Papua, the eastern region of Indonesia, as well as some part of Australia. I decided to go with Paradisaea apoda, or Greater bird-of-paradise. It features plume from its back, and it is not tail!

## Design

I finished my design 2 weeks after starting. It was a mistake though, I got satisfied too early and was inexperienced. When I showed it to someone, they would be confused. I forgot about it until Ivan submitted his design in Origami-Dan's design contest. It was a glorious model that he made!
 Version 0.0

 CP for version 0.0: tiles of bird base and Y molecules, with strip graft for legs and plume.

That month's design contest theme was "aerial". I spent some time to grind on bird models, such as Cuong's eagle, Hoang Trung Thanh's eagle, Kamiya's yatagarasu, and Kamiya's lyrebird, and finally come up with the frigate bird design. With those experiences, I understand the essential parts of bird design: feathers.

I couldn't find easy way to graft the wings, so I started over. The idea of bird base on top left was kept, and I replaced the other part with this trapezoid with 45 degree structure.

The cool thing about this trapezoid is, once you do sink in and out on it, you will get pleats that is ready to be boxpleated. All the line intersections lie within the grid.

Now I can just add pleats there and square pack the wings and legs. I thought it is cool that the plume pleats are reused for legs and wing feathers. The CP became hybrid traditional base + graft with boxpleating.

The trapezoid is divided vertically into 18 equal parts. I did that because I wanted 2 flaps with 6 strips of graft. We can make 4 toes on one of them to make the legs, and the other became the wing's feathers. It worked, but the wing feathers were too little and the plume was too large. Not to mention the grid is kind of cursed. Dividing that section into 9 then 18 was nightmare.

Then I thought, why not just spend the entire edge to corner for the wing feathers? Just extend the feather pleats all the way to the bottom. To do this, I added the trapezoid's width. This also resulted in adding the bird's body size except for the plume, equivalent to reduce the plume size. I didn't want to deal with cursed grid so the trapezoid is divided into 16.

The strategy worked, but there exist a funny river that messed up the base.
 Funny river highlighted in green.

Removing the river was easy, just shrink and align the bird base's wing flap with the boxpleated wing flap.

The gap can be filled with strip graft. I will do sink in and out there, and donate the pleat for more wing feathers. Actually the pleat also allowed the creation of tail feathers. By the way the tail is represented by 2 flaps, and their shape in the CP is weird polygon.
 Two distinct flaps shaded with green and purple will become tail.

This CP was quite satisfying, but I learned my lesson to not get satisfied too early. There's a weakness where the bird's head, wings, legs, and tail are connected into one point. There's no river at all! I reviewed other bird models, and saw that there should be river between wings and legs. River can be made by extending the trapezoid structure once more, and modifying the bird base into half frog half bird base. That hybrid traditional base allowed river to separate the wings and legs. I also lengthened the legs for less mushy thinning.
 River shown in green. Note that it doesn't align with the grid, so the wing's actual length is slightly more than 8 square units.

The basic structure was finally satisfying. Next thing was how on earth should I shape the plume. I reviewed the existing model on bird with decorative feathers: Maekawa's peacock and Kamiya's lyrebird. Both of them used Miura fold, and I think I should try that. The difference is I have to make the plume curved, and I figured out it can be done by alternating the pleat angle.

I test folded the plume and just improvise the pleat angle. It worked, but I realized that the crease would not intersect at nice places. There will be places where the pleat is degenerate; producing tiny gusset-like structure. See the picture below.

After doing some calculations, making the pleat intersect at regular places can be achieved by spacing the pleat $$1 : \sqrt{2}$$ alternatingly. Sometimes it is funny on how the number $$\sqrt{2}$$ keep re-occurring in origami design (alright it's because the angle is 22.5 degree).

And finally the design is done. The reference is $$4 + \sqrt{2}$$, with the original trapezoid get vertically divided into 16, and the additional strip graft divided into 4.

Folding Miura fold is actually not straightforward. I used Kamiya's sequence that involves creasing through thick layers, slide one layer, sink, and repeat. Without keep readjusting the crease reference, creasing through thick layers makes the accuracy terrible. I folded the plume 6 times to get used to it and get "reasonably accurate" result.

 The plume practice.

Yeah... finally it is done. I am happy with the result, but I've lost my confidence in my sense of art-appreciation because often time I think something looks good, others will say otherwise. I had no idea if this is good model, or is it just me who thought of that. Luckily the responses are positive, so now I am happier.

Lesson learned in this model: do not get satisfied quickly and hybridize the structure is really fun. Hopefully you can learn something from this post.

### Warped and Wrinkled Paper Curse

After starting using Carboxy Methylcellulose (CMC), I began to wonder if my setup wasn't right. The problem was my double tissue would always peel itself when drying. There will be high pitched popping sound from the paper every now and then. Finally it would be completely off the surface. Whereas on every tutorial I saw, the paper will still stick to the surface and we have to peel it off. The bad part is the paper will be warped; it's not flat. It is difficult to fold a straight line on paper like this. Imagine precreasing a grid or locating references when your fold can be bent due to the paper's bump. I have theory on why the warp happened. Before going to that, it is important to know that: When a paper is wet, it expands. When it dries, it will return to the original size. However it will keep its shape when it is wet, meaning that if it is bent when wet, it will retain that bend when dried.  When my paper dried partially, that region will shrink. This created differe

### Origami Ibex

Ibex is a type of wild goat found on Eurasia and North/East Africa. Easily identifiable by its long curved horn full of ridges, which is what I'm trying to express here. Nubian ibex is vulnerable to extinction due to competition with livestock and habitat loss. Ibex has been nearly extinct multiple times in the past because of hunting and unable to compete against livestock. The most recent extinction was Pyrenean ibex, in the year of 2000. Image source:  https://animals.sandiegozoo.org/animals/nubian-ibex I want to make my model to be instantly recognizable as an ibex, not a goat. Horn ridges are rather specific for ibex, so I tried to represent that with spike structure commonly used on insect legs.

### Origami Helmeted Hornbill

Helmeted hornbill is a huge hornbill with round casque, featherless throat, spiky hair, and two very long tail feathers.  Unlike other hornbills, its casque is solid and for some reason some people like it. It is sought as valuable item just like elephant's tusk. Overhunting has driven them to be critically endangered. This is the most challenging subject that I've attempted so far.