The shaft can have different cuttings and the heads of the nails come in different sizes. The different composition of the nail makes it useful in different construction projects. Some nails are fine for finishing work while others are rough for better gripping. Screws come in a variety of lengths and widths. The heads can be flat, round, or oval, and have a slatted or cross mark on the top.
Some screws have a hexagonal head and are turned by wrench.
There are eye screws, cup hook screws, and dry wall screws which are used in specific situations. Wall mountings come in molded, fiber, and aluminum. They're used as anchors and work with screws and nails. If you have a hollow wall you should use wall expansion anchors.