WATCH FIRST, THEN READ ON!
The dotes change color, constantly cycling through different hues. The dots suddenly move in a circle and simultaneously stop changing color. Then they freeze and go back to changing color again. This is what you saw, right? Well you're wrong! Your brain has tricked you! Blast! Stupid Brain!
"While you may not see it, the dots in the video above are always changing color, even when they are moving. This visual illusion takes advantage of a phenomenon called "change blindness" in which your brain cannot detect changes when it is distracted by movement and other visual stimuli."
Found at gizmodo.com