Disappearer consists of a transparent plastic platform placed over a big disk than can be turned. A yellow dot on the platform is located over the center 0f the disk, and other items are located away from the center. Users are instructed to stare at the yellow for a few seconds and then rotate the disk while continuing to focus on the dot. Previously clearly visible items on the platform disappear when the platform rotates. Researchers don't fully understand this effect, but it does show that what viewers pay attention to can affect what they see. Here, it appears that the background motion draws the viewer’s attention—causing the visual system to temporarily stop responding to the shapes that are not moving.