This is famous Kawasaki Rose designed by Dr. Toshikazu Kawasaki.
A flower is made with a square sheet of paper without cutting.
The process is too complicated to explain.
White rose and rosebud.
These are Fukuyama Rose.
It is easier than Kawasaki Rose but still difficult.
Fukuyama rose folded with cloth.
This is a Rosebud Cube designed by Mr. Kunihiko Kasahara.
It's only a cube but difficult.
Origami is easy and abstruse paper craft.
If you have interest, you may find how to make by search.