Once you have successfully brought the **xprism3**
window (Figure 3) up
in your screen, the next logical step would be to plot something
in the window. First you
must select the **Plot** button on the left of the
window. There are two ways
of plotting a function. One is
to use a file already made and use the **
Input File** button.
The other option is to create the function *during* the
**xprism3** session using the **
Input Function** button.

Ok, so you have chosen to input a file you already have instead
of typing a new one in. A good solid choice if you are going to
be working with the same functions more than once. So you have
clicked on the **Input File** button and brought up another
window (Figure 4) which you must
fill. I inputted a file called `test2.text`

from
my xprism3 directory. Note that you must put in the *entire*
path name in the **Filename** box. Khoros is working from
its own home directory, not yours. ` test2.text`

contains the following information:

```
f(x,y) = sin(x)*cos(y) + x**2
```

x=(-pi,3.14,40)

y=(-pi,3.14,40)

The correct syntax to use for the mathematical symbols is
available in the Help box in the **Input Function**
window.
The `x=`

and `y=`

parentheses contain
the left endpoint, the right endpoint, and the number of
points in between, respectively. Since the text file already
has the **Points to Be Displayed** information in it, I
ignored that section of the window. For **Plot Type**,
I chose my favorite, which is **Color Mesh**. I skipped
the sections above the **Plot Type** since they have to
do with **Raw Data Files**, and my data file is a function.
Since I am done, then I click on the bottom button, **Plot File**.
You may change your mind about the **Plot Type** and click
on **Plot File** again. **Xprism3** will draw the plots
*on top* of each other, with the plot legends below.
You may use the Hide option
to just look at one at a time. Figure
5 shows the plot of `test2.text`

using the
**Color Mesh** option.

To create functions during the **xprism3** session, you must
choose the **Input Function** option. The window will
then change to something similar to
Figure 6. If you have made this choice you *must* enter
in a function in the box marked ** Function f(x, y)=**.
The **Help** box below will help you with the required syntax.
Using the *wrong* syntax, the function I entered was

* sin(x²) -2cos(y²) -x³y³ *

Please notice that I could not have entered the function in that
form into the box and do *not* try to cut and paste it in there.
Another rule to remember is that the function must be in terms of
**x** and **y**. You have the option in this window to change
the *x* and *y* parameters, but make sure that
the function exists for those values. At the bottom of the window,
you may select a **Plot Type**. Since **xprism3** will
graph up to 20 different graphs at once, you may try each of these,
but I do not recommend it. **Xprism3** will graph them *on top
* of each other, making clarity impossible. I have
chosen **Color Mesh** (which I will always do if given any freedom
of choice). Once your selection is made, click on the **Plot
Function** button and your graph will appear in the main **xprism3**
window. Figure 7 below is the result of the choices made in
Figure 6. It should look quite
familiar.