During Coldplay’s Lovers in Japan music video, the band members use some sort of pen with a light on the end to make it look like they’re writing in thin air. I was going to look into this, and see if i could figure out a way to do this on my own. Unfortunately, I have no idea what it’s called, and don’t even know what to search. I was hoping to get some information on this subject and how i would go about doing it. Thanks!