I've always liked screens full of randomly colored pixels. They're interesting to look at and the programs that draw them are fun to watch.

The challenge

Fill your screen, or a graphical window, with colored pixels.

The rules

• Your program must have an even chance of picking all colors (i.e in the range #000000 to #FFFFFF), or all colors that can be displayed on your system.
• Your program must continue to display random pixels until manually stopped (it cannot terminate on its own).
• Pixels can be any size, as long as your output has at least 40x40 "pixels".
• Your program must run at such a speed that it can replace every pixel on the screen/window at least once after running for three minutes.
• Your program must choose truly random colors and points to replace, i.e. random with all points/colors equally likely. It cannot just look random. It must use a pRNG or better, and the output cannot be the same every time.
• Your program must have an equal chance of picking all colors each iteration.
• Your program must replace only one pixel at once.
• Your program cannot use the internet nor your filesystem (/dev/random and /dev/urandom excepted).

Example

Your output could look like this:

The winner

The shortest answer in each language wins. Have fun!