The shelf in the first picture is made of red oak plywood. You can choose the wood type, color and design as you like for your project. In case if you need more help understanding this project, you can refer the source link below. It discusses various items used, steps and tips and personal experience of the author who personally built a Zigzag shelf.
I’m 91 years old, but I still enjoy spending time in the wood shop. I like to make wooden toys and give them to my great-grandkids and charity groups. One trick I’ve learned over the years is to use emery boards—the kind for filing fingernails— to sand small parts. Emery boards come in different sizes, and some are more abrasive than others, so I keep an assortment on hand. — Joe Aboussleman
The progenitors of Chinese woodworking are considered to be Lu Ban (魯班) and his wife Lady Yun, from the Spring and Autumn period (771 to 476 BC). Lu Ban is said to have introduced the plane, chalk-line, and other tools to China. His teachings were supposedly left behind in the book Lu Ban Jing (魯班經, "Manuscript of Lu Ban"). Despite this, it is believed that the text was written some 1500 years after his death. This book is filled largely with descriptions of dimensions for use in building various items such as flower pots, tables, altars, etc., and also contains extensive instructions concerning Feng Shui. It mentions almost nothing of the intricate glue-less and nail-less joinery for which Chinese furniture was so famous.