The Cygwin environment for MS-Windows now includes a high-quality, free X11 server, X11 clients, and an X11 development package including the standard X11 libraries and include (*.h) files. If you have installed the Cygwin X11 packages, the X11 version of plt (xplt) will be compiled and installed automatically if you follow the standard instructions for installing plt under MS-Windows.
To use xplt, you must be running the X server, which you can do using the command startx in a Cygwin terminal emulator window. The default installation starts the X11 server, the fvwm window manager, and several xterm windows. From any of these terminal windows, you can run plt as described in the plt Tutorial and Cookbook, following the instructions for running Unix versions of plt. If you have not tried this previously, you may want to try running "make xdemo" from the doc directory of the plt source package to see how this works.
The fvwm window manager displays a frame whenever a new window is to be opened; use the mouse to drag the window to the desired position, then resize it by clicking and dragging the window edges as desired. Once the window has been placed and sized in this way, its contents will appear.