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.
Build this handy stool in one hour and park it in your closet. You can also use it as a step to reach the high shelf. All you need is a 4 x 4-ft. sheet of 3/4-in. plywood, wood glue and a handful of 8d finish nails. Cut the plywood pieces according to the illustration. Spread wood glue on the joints, then nail them together with 8d finish nails. First nail through the sides into the back. Then nail through the top into the sides and back. Finally, mark the location of the two shelves and nail through the sides into the shelves. Don’t have floor space to spare? Build these super simple wall-mounted shoe organizers instead!
Sanding small items is tricky, as they’re hard to clamp in a vise to work on them. So instead of bringing the sandpaper to the workpiece, I bring the workpiece to the sandpaper. I glue sheets of sandpaper to a piece of plywood; 60 and 100-grit on one side and 150 and 220-grit on the other. Spray adhesive works well for this. Since there’s sandpaper on both sides, my sanding board doesn’t slide around on the bench. Check out these small projects!