Historically, high-status items, such as metal tableware, were often recreated for the mass market using pottery which was a cheaper material. In certain cases, efforts were made to recreate the rivets in the metal originals by adding pellets of clay to the pottery version for example. The mortice and tenon joints present in the trilithons of Stonehenge may be examples of skeuomorphs, derived from earlier timber structures.
In the modern era, cheaper plastic items often attempt to mimic more expensive wooden and metal products though they are only skeuomorphic if new ornamentation references original functionality, such as molded screw heads in molded plastic items. Blue jeans have authentic-looking brass rivet caps covering the functional steel rivet beneath, and a pocket watch pocket; digital cameras play a recorded audio clip of a conventional camera shutter opening and closing. Such ornamentation is not necessarily non-functional: the watch pocket is now used for coins, and ribbing on a hunting knife handle (skeuomorphic of vines binding wooden handles to a metal or stone blade) adds grip. An interesting example from the field of consumer electronics is the presence of a circle on the face of the Zune - this is not needed, as the buttons exist in a four-way configuration, but is shaped to bring to mind the touch-wheel interface of the iPod.
Many music and audio computer programs employ a plugin architecture, and the majority of the plugins have a skeuomorphic interface to emulate expensive, fragile or obsolete instruments and audio processors. Functional input controls like knobs, buttons, switches and sliders are all careful duplicates of the ones on the original physical device being emulated. Even elements of the original that serve no function, like handles, screws and ventilation holes are graphically reproduced.
The arguments in favor of skeuomorphic design are that it makes it easier for those familiar with the original device to use the digital emulation, and that it is graphically appealing.
The arguments against skeuomorphic design are that skeuomorphic interface elements take up more screen space than standard interface elements; that this breaks operating system interface design standards; that skeuomorphic interface elements rarely incorporate numeric input or feedback for accurately setting a value; and that many users may have no experience with the original device being emulated.
Skeuomorphs are differentiated from path dependent technologies such as the QWERTY keyboard which first appeared on the typewriter in 1873. The layout was designed so that frequently used pairs of letters were separated in an attempt to stop the typebars from intertwining and becoming stuck, thus forcing the typist to manually unstick the typebars. Though no longer required since electrical switches beneath the keys replaced mechanical typebars, the QWERTY layout is still used for English language computer keyboards because of the existing investment in QWERTY typing education. Scholars therefore differentiate left-over technologies like the QWERTY keyboard, with its economic justification, from the pure design touches of the skeuomorph.
It has been argued that toenails and the human appendix are examples of biological skeuomorphs.