Accidental discovery

Maybe I'm the last to notice this, I'm rarely the first, but tonight I was watching a video on YouTube and had to pause it for a moment. Meaning to scroll the page down to read the comments, I hit the cursor down key. Instead of scrolling down though, the little rotating circle on the video turned into a game of Snake! Hitting left, right, up and down I could steer the snake in an attempt to run over a single flashing dot, somewhere on the video screen. Hit that dot and the snake grows longer. Not sure how long it's been there or if it works on other sites with the same rotation icon while loading videos, but I thought it was a cool little Easter Egg to find tonight.