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.
The description below is an outline for how the course will proceed.  We intentionally maintain a level of flexibility in our curriculum to adapt and respond to the needs of each group of students depending on aptitude.  Each project has a basic standard of completion as well as design opportunities for elaboration and exploration of more advanced techniques.   Our instructors will guide you through projects as is best suited for your ability level.   
To mark the centerline, set a compass to span something more than half the width of the leg. Draw an arc from corner of the leg. The point where the arcs intersect will be on the centerline. With a centerline point on each end of the leg, place a scribe on the point, slide a straightedge up to touch the scribe. Do the same on the other end. When you have the straightedge positioned so that you can touch both points with the scribe, and in each case it is touching the straightedge - without moving the straightedge - scribe the line. Use scribes, rather than pencils or pens, because they make more precise marks.
We are especially proud of Post Woodworking’s Brunswick style shed. It has all the rugged features and simple, beautiful mystique of a Maine coastline. Natural-wood siding options, in pine or cedar, offer a rustic aesthetic. Or, choose a vinyl color that complements our home. Once inside the Brunswick, its unique, two-sided sloped roof maximizes headroom, making space for you to better maneuver a rake. Black architectural hinges and hardware lend distinguished contrast and quality to this basic but appealing storage solution.