par() function can be used to set or query graphical parameters.

> par("lwd")
[1] 1
> par("fg")
[1] "black"

Let's use mfrow= to split the plotting device screen:

> par(mfrow=c(2,2))
> curve(cos, -2 * pi, 2 * pi, col="blue")
> curve(cospi, -2, 2, col="blue")
> curve(sin, -2 * pi, 2 * pi, col="red")
> curve(sinpi, -2, 2, col="red")

In case to reset to the original parameter settings, you may first save the default, then recover it later.

> opt <- par(no.readonly = TRUE)
> par(opt)

List of default graphic parameter values: