$\frac{\text{U}\text{N}\text{I}\text{V}\text{E}\text{R}\text{S}\text{I}\text{T}\text{Y}OF\text{C}\text{A}\text{L}\text{I}\text{F}\text{O}\text{R}\text{N}\text{I}\text{A}}{U\text{D}\text{I}\text{S}}$

Which design feature of language is the following description an example of: The $"$no smoking" sign contains two components $1.$ a picture of a cigarette and $2.$ a slash meaning $"$no$"$