Now, if you take two of these blocks and simply stack them on top of each other, you get a pattern that resembles the LED "8":
Below you see an example output:
Try to select the above "hello" with your mouse--it's neither an image nor text.
The interesting thing about this is that you can use it to make text without actually having that text in the source code. This is great for preventing crawling robots and spammers from reading your text, while still allowing your human readers too see things fine. Some applications of this might be to cloak or email address, generate CAPTCHAs, or to do evil search engine optimization by hiding text from Googlebot. This method might be better than the straightforward method of rendering your text as images because it requires the robot/spammer to have
- the ability to snapshot/render a certain region of the screen
- Optical character like recognition capability