That this poinsettia is published now is of course bad timing, but it is beautiful, has a number of interesting moves, and then you have plenty of time for learning it before next Xmas.
The flower appeared in af conscious attempt to design a poinsettia. This plant is special in that what we perceive as the flower, are ordinary leaves while the flower is some discrete gewgaw in the center. That also means that the leaves are placed very discrete compared to the normal appearance of petals.
The first versions looked like below. The first flower fixes the leaves together. In the next two they are freed a bit more via an internal fish base which is symmetric instead of locking into the pocket of the neighbor leaf.
I was very proud of this way of assembling the corners, as a fold it is quite elegant. But the leaves are still too attached to eachother, and overall the model appears too flat. Another solution appeared with the elegant triangle version. The angles of that makes the first solution less natural. Instead the corners were folded in a V-shape freeing more paper and letting the interleaf space go all the way to the center.
This technique was refined in the square version. Compared to the previous versions the leave interspaces go to the center, the leaf centers close tighter with only the stripe of the real leaves, and the center of the flower has more structure.
As the picture of the live poinsettia above shows, the real poinsettia has a three-fold symmetry in a fractal pattern. But often the leaves develop irregularly thus blurring the symmetry, and pictures at google show that illustrators often perceive poinsettias as five pointed stars. Thus the most impressive version is the pentagonal (diagram) which in particular has a characteristic center.
It takes me 20-40 minutes to fold. But there are several interesting moves in the folding sequence, and many design variations, including how to make the center, the leaf corners, the leaf finish, and choosing the polygonal order (3, 4, 5 seem best).
Enjoy! And happy Xmas.