Optical Illusion as Web Design Technique

Look at this website. It is an Australian company that sells and ERP product. Whatever.

But look at the way the graphic above the main menu makes the menu itself look as though it is thicker at one end rather than the other.

I imagine this was entirely unintentional by the company web designers, and the end result looks a bit disconcerting.

However, it did lead me to wonder if there might be some room for using optical illusions to create subtle design elements on a web page.

I'll add it to my list of millions of things to consider...