Who needs another captcha script right. Well, I actually only initially started this script for another reason and I thought it would make a cool captcha.
This class can create a captcha from a set message or a generated random message for verification all without using any images. It creates characters by shading in table td cells with a user set background color and leaving other cells transparent or whatever you set it to. The result is a grid of colored cells that draws out characters similar to an led sign. Many of you may hate the usage of tables in this way, but I think it's pretty cool.
Certain characters in the captcha text can be highlighted or even flashing. You can validate using the whole captcha text, the highlighted/flashing text or the non-highlighted/non-flashing text.