Test Tube is YouTube’s area for trying out new features. Tonight I played with a new item called Warp. You choose one of many floating circles to click on in order to watch a video. What you select affects new circles that bubble up, so to speak. As you continue to choose a line connects the vids you've chosen. There must be a maximum because earlier ones I know I watched were no longer connected. Also, there's some kind of color code to the circles. In the upper left corner there's a grouping of ten colored dots corresponding to the floating circles. If you want to exit a video quickly, there's a collapse box with an "x" on the lower right of each video window. 'Not sure how much this would help sifting, but it was interesting to test . . .