What would the plot of an two sided digital signal look like? Please, take a look at section, 1.2.3 (Signal Duration), Page-03, of the book Shaum's Outlines: Digital Signal Processing by  by Monson H. Hayes.

According to the definition, I can imagine how a right-sided and a left-sided signal look like.


But, I cannot visualize a two-sided signal.

What would an two sided signal look like?

All I need is to see a double-sided signal. As far as I know, a double sided signal is a complex exponential signal. So, that means it should be a plot of a complex exponential function. Am I correct?
A function of $x$ is right-sided if and only if there is some
$x_0$ such that the value of the function is zero for all $x &lt;
x_0$, and left-sided if and only if there is
some $x_0$ such that the value of the function is zero for all $x &gt;
x_0$.

Likewise for signals with time represented by $x$. A double-sided signal has neither restriction. For example a Gaussian function and $\sin(x)$ (both pictured below) are double-sided.

$f(x) = \frac{e^{-\frac{x^2}{2}}}{\sqrt{2 \pi }}$

$f(x) = \sin(x)$