I figured this would have to do with multiple lasers interfering with each other. This is in some ways even cooler.,(reply>), It's hard to control the phases of visible light lasers accurately enough, that is my impression at least. Visible light has a frequency in hundreds of terahertz. But it'd be a cool tech to have. I mean, phase control of visual light might yield actual holograms. <br><br>Warning, I'm not an expert.