notes
The above is a randomly generated, one-dimensional cellular automaton, using Rule 110. This version is written in JavaScript and is generated at the client. The source code is here.
This page is generated by outputting a series of Unicode ‘BLACK SQUARE’ (U+25A0) characters into a <pre> block with a font size of .5pt, which is so small they are rendered as a single pixel. View the page source to see the pattern.
The pattern here is limited to a 450 by 550 matrix, but you can easily take the code and run it on your local server as a simple way to observe patterns of a much larger size. There is a Java-based version of this page that runs the automaton at the server here.
For Windows users: if you have “Smooth edges of screen fonts” checked in the Display Properties, the image may be somewhat gray, but it is still visible.
For Mozilla users: if you have a minimum font size set to other than “none” the effect will probably be ruined and you'll see the ‘M’ pattern directly.