“A leaf bud is much smaller in both length and breadth than the leaf it will become. After bud break the leaf will begin to grow but even at birth the leaf is too big for its cocoon. How can something be so tightly packed and expanded in both length and breadth as its opened? The principle of leaf opening can be demonstrated in 10 minutes with an origami experiment known as Ha-ori (meaning ‘leaf-fold’).”1

I still haven't been able to find a nice clear tutorial for this origami exercise. For now, here are some okay pictures/videos I captured a few years ago. Perhaps someday I'll redo them.

Video tutorial:

Image tutorial:

1 / 12

More to Explore~

Learn more about origami’s relationship to engineering, design, biology, robotics..

https://www.pbs.org/wgbh/nova/article/origami/
The Origami Revolution | Math and Science Modernize an Ancient Tradition | Grades 9-12 Mathematics Teaching and Lesson Resources
Discover parallels between the natural world and origami—the Japanese art of paper folding—and witness how artists, mathematicians, and scientists are pioneering complex new designs, in this video from NOVA: The Origami Revolution. While origami is steeped in tradition, computer programs are being used today to develop new, more complex designs so that almost any three-dimensional object can be translated into a two-dimensional pattern that can be folded to model the object. This resource is part of the NOVA Collection.
https://rmpbs.pbslearningmedia.org/resource/nvtor-sci-moderntrad/wgbh-nova-the-origami-revolution-math-and-science-modernize-an-ancient-tradition/#.WYMj39MrLOQ

Dig Deep into the science and mathematics of leaf-folding

(PDF) The geometry of unfolding tree leaves
PDF | Leaves of hornbeam (Carpinus betulus) and beech (Fagus sylvaticus) were modelled to a first approximation as plane surfaces, with straight... | Find, read and cite all the research you need on ResearchGate
https://www.researchgate.net/publication/25453609_The_geometry_of_unfolding_tree_leaves

Try this origami simulator that lets you explore and download different folding patterns

Originally published in 2020, here.