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 recently came across this beautiful wooden swing set, which was made in the shape of a boat. Cool, isn’t it? The very first look was enough for me to start loving it. Although I haven’t yet tried building one myself, I am definitely going to. Later I realized that you can also build a baby cradle with the same idea. After all, what can be more calming than the tender rocking of a boat? This swing set will surely help your child get more gentle sleep.