Magic circles on Facebook - funny trick

I found a cool trick on Facebook. Press Up, Up, Down, Down, Left, Right, Left, Right, B, A, Enter key, & magic circles will appear. The effect can be seen when scrolling the page, clicking, or typing. I have taken the screenshot of the page:



What actually are these Magic Circles on Facebook:
This is Konami code used in Konami video games as cheat. Facebook displays the circles as lens flare effects as a fun stuff for Facebook users. These are also used by different websites on the web.

You can remove it by refreshing the page. In Chrome and Safari it is removed by navigating to another facebook page but not in Internet Explorer and Google Chrome.