(WPF)

Rubbery leaves have two sides. The upper side--facing the light--is a kind of protector of the lower side--more or less facing the earth. The upper part of the leaf is usually the shinier side. It is composed of regularly shaped cells. The lower side contains the more chemically active organs involved in air intake and regulation of light. You can see this defensive pattern in the way the upper and lower faces of the leaf appear.

https://youtu.be/9RV7OVMd47A