This sweet Rose is designed by Joan Sallas. It is from a single square, is based on thirds and has a square twist. It also is a delightful blow top.
Origami with Love by Nick Robinson pp. 26-27
One square of origami paper - kami works fine. Size 6 inch (15 cm) is good for learning. 3 or 4 inch (7.5cm or 10cm) also works well.