Petal fold


Post is a part of a larger series (Folds):

The petal fold belongs to the group of moderately complex folds. It is so because it cannot be described as a fold along a single line. 

Nevertheless, it is regularly performed by absolute beginners. You see, the petal fold is often used as one of the folds during the folding of the classical bird base (figure 1). Hence, even if you are an absolute beginner, there is a good chance that you already fold one.

Figure 1

Petal fold  – simple implementation

But why I have said that the petal fold is “most often” used during bird base folding.  Is it possible to fold a bird base without resorting to the petal fold implementation? Well, strangely enough, in the case of bird base, the answer is yes. If you analyse the procedure shown in figure 2, you will notice that there is no petal fold whatsoever. Instead, there are two inside reverse folds (A) and one simple fold (B). Nevertheless, the final result is the same.

Figure 2

If you compare this new procedure with the original one, you will immediately realise that the initial procedure asks for simultaneous folding of multiple creases. On the other hand, the second approach is more of a sequence of simple folds. 

So, what is petal fold after all? Is it a sequence of few simple folds, or is it a fold in his own right? 

Before I answer that question, let me show you another simple example (look at figure 3).

Figure 3

Again we have performed a petal fold (figure 3). But, if we try to implement the same approach as one, shown in figure 2, we will soon find out that the petal fold is a bit more complex than one could expect. In other words, a simplified approach shown in figure 2, wouldn’t work here, or at least, it wouldn’t work so elegantly. What is this telling us? Well, it is telling us that if there is no elegant way to break down a petal fold into a sequence of simple folds, then the petal fold must indeed be a fold in its own right. We can even pre-crease almost all necessary folds in advance (look at figure 3), and still, we wouldn’t be able to fold it in a stepwise manner.

What’s even worse, in more complex applications of a petal fold, we will be forced to perform petal fold without pre-creases. In other words, you will have to perform petal fold on the fly, which is quite hard for origami beginners. That is the sole reason why the petal fold is considered moderately complex.

Petal fold and rabbit ear

If we analyse previously shown petal fold examples, we might realise one unusual feature of petal folds. They, in fact, consist of two symmetrically placed rabbit ears. Look at figure 4. 

Figure 4

So, is this a definition of a petal fold?  The petal fold is nothing more than two symmetrically placed rabbit ears. Maybe, and maybe not. But, to be honest, this is the definition I can agree on. After all, the most quoted example of a petal fold is the one on the bird base. And if you analyse the bird base (look at the blog post on a traditional origami basis), you will see that the bird base consists of nothing but the number of rabbit ears. 

So the definition seems logical? But, unfortunately, one can find much more complex implementations of the petal folds. For example, in Shuki Kato’s book; Nature Study, on page 36 (steps 7-10), you can find one such more complex example (figure 5).

Figure 5

Is it possible to claim that the just shown petal fold also consists of two symmetrically placed rabbit ears? I don’t think so. But again, even the author, Shuki Kato, wasn’t sure that this is a genuine petal fold, so he called it a Petal-like fold. So, I suggest sticking to the previous simple definition.