At times, white rings will appear in the outer layers of the circles. Dash at the correct moment to collect them. The rings are a game currency used to purchase new color themes. Two rings are also awarded after completing missions. Because the colors are purely cosmetic, you can skip ignore rings if collecting them is too dangerous. In fact, some of the new color schemes make the game more difficult due to their distracting hues. You can also earn three rings by watching advertisement videos.