Thanks, I cannot get it to run with my vncviewer (TightVNC Viewer
version 1.3.9)

How should I call vncviewer and your Main binary?

./Main 200 200 5900

after this, the program should start listening to port 5900

You can check if things are fine by telneting to localhost:5900, you should see this -

ck@ck-desktop:~/lab/Chitra$ telnet localhost 5900

Trying ::1...

Trying 127.0.0.1...

Connected to localhost.

Escape character is '^]'.

RFB 003.003

After this, you can use vncviewer to connect to localhost (5900 is the default port for vnc)

P.S. after getArgs in Main.hs use
case args of
[x, y, p] -> ...
_ -> putStrLn "usage: Main xres yres port"

instead of "!!"