6 ways\Dye Fabric Black Naturally - Natural Black Fabric Dyes -Covering rusty iron nails with vinegar- fill a non-reactive tub with the nail and vinegar. black dye must be set into the fabric using alum to make it permanent.
Cut legs A & rails B, C to size. Cut hand hole & mortises for hinges in back rail. Cut half lap joints in legs & rails. Lay assembly on bench & clamp swing-leg assemblies on top in open position. Make sure top edges & outside faces of swing-leg rails
This project is not for the average DIYer as it requires access to a CNC machine to cut the pattern in the ply. But if you have a very good hand and an equally good jigsaw you should have no difficult (Diy Furniture Building)